#include <iostream.h>
 #include <graphics.h>
 #include <string.h>
 #include <stdlib.h>
 #include <conio.h>
 #include <math.h>
 #include <dos.h>

 const max_length=10;


 class Evaluator
    {
       private:
        char infix_expression[25][6];
        char postfix_expression[25][6];

        char char_stack[10];
        long int_stack[max_length];

        int int_top;
        int char_top;

        int postfix_rows;
        int infix_rows;

        int input_characters_count;

       public:
        void set_initial_values( );
        void show_main_screen( );
        void get_infix_expression( );
        void show_infix_screen( );
        void char_push(char);
        char char_pop( );
        void show_char_stack(int);
        void show_explanation(int);
        void show_infix_to_postfix_convertion( );
        void int_push(long);
        long int_pop( );
        void show_int_stack(int);
        void show_postfix_screen ( );
        void show_evaluation_of_postfix_expression( );
        void show_summary( );
    };

 /*************************************************************************//*************************************************************************//***********************  Function Definitions  **************************//*************************************************************************//*************************************************************************//*************************************************************************///----------------------- set_initial_values( )  ------------------------///*************************************************************************/void Evaluator::set_initial_values( )
    {
       int_top=-1;
       char_top=-1;
       infix_rows=0;
       postfix_rows=0;

       for(int count_1=0;count_1<max_length;count_1++)
      {
         int_stack[count_1]=0;
         char_stack[count_1]='\0';
      }

       for(int count_2=0;count_2<25;count_2++)
      {
         for(int count_3=0;count_3<6;count_3++)
        {
           infix_expression[count_2][count_3]='\0';
           postfix_expression[count_2][count_3]='\0';
        }
      }
    }

 /*************************************************************************///-----------------------  show_main_screen( )  -------------------------///*************************************************************************/void Evaluator::show_main_screen( )
    {
       cleardevice( );

       for(int count_1=0;count_1<340;count_1+=20)
      {
         setfillstyle(6,1);
           bar(getmaxx( )/2-count_1,getmaxy( )/2-count_1,
                   getmaxx( )/2+count_1,getmaxy( )/2+count_1);
      }

       for(int count_2=0;count_2<15;count_2++)
      {
         setcolor(count_2);
           rectangle(5+count_2,count_2+5,getmaxx( )-5-count_2,
                               getmaxy( )-5-count_2);
         delay(10);
      }

       delay(500);

       char expression[10][2]={"E","x","p","r","e","s","s","i","o","n"};

       int x=80;
       int y=50;

       for(int count_3=0;count_3<10;count_3++)
      {
         settextstyle(1,0,8);
           setcolor(0);

           moveto(x-3,y+2);
         outtext(expression[count_3]);

           moveto(x-2,y+2);
         outtext(expression[count_3]);

           moveto(x-1,y+2);
         outtext(expression[count_3]);

           setcolor(12);

           moveto(x,y);
         outtext(expression[count_3]);

           moveto(x+1,y);
         outtext(expression[count_3]);

           moveto(x+2,y);
         outtext(expression[count_3]);

           moveto(x+3,y);
         outtext(expression[count_3]);

         x=getx( );
         delay(150);
      }

       delay(500);

       char evaluator[9][10]={"r","or","tor","ator","uator","luator",
                  "aluator","valuator","Evaluator"};

       for(int count_4=0;count_4<9;count_4++)
      {
         settextstyle(1,0,8);
           setcolor(0);
         outtextxy(217,122,evaluator[count_4]);
         outtextxy(218,122,evaluator[count_4]);
         outtextxy(219,122,evaluator[count_4]);

           setcolor(12);
         outtextxy(220,120,evaluator[count_4]);
         outtextxy(221,120,evaluator[count_4]);
         outtextxy(222,120,evaluator[count_4]);
         outtextxy(223,120,evaluator[count_4]);

         delay(150);

         if(count_4<8)
        {
           setfillstyle(6,1);
             bar(210,140,580,200);
        }
      }

       delay(500);

       settextstyle(1,0,4);
     setcolor(0);
       outtextxy(150,52,"Arithmetic");
       outtextxy(151,52,"Arithmetic");

     setcolor(12);
       outtextxy(152,50,"Arithmetic");
       outtextxy(153,50,"Arithmetic");

       delay(500);

       setcolor(15);
     line(495,415,580,415);
     line(496,416,580,416);

     line(495,449,580,449);
     line(496,448,580,448);

     line(495,415,495,449);
     line(496,417,496,448);

     arc(580,432,270,90,17);
     arc(580,432,270,90,16);

       setcolor(7);
     line(497,417,580,417);
     line(498,418,580,418);

     line(497,447,580,447);
     line(498,446,580,446);

     line(497,417,497,447);
     line(498,418,498,446);

     arc(580,432,270,90,15);
     arc(580,432,270,90,14);

       setcolor(8);
     line(499,419,580,419);
     line(499,445,580,445);
     line(499,419,499,445);

     arc(580,432,270,90,13);

       setcolor(9);
       setfillstyle(1,9);
     bar(500,420,580,444);

     pieslice(580,432,0,360,12);

       settextstyle(2,0,6);
     setcolor(0);
       outtextxy(508,422,"Evaluate");
       outtextxy(509,422,"Evaluate");

     setcolor(14);
       outtextxy(510,420,"Evaluate");
       outtextxy(511,420,"Evaluate");

       setcolor(15);
     line(425,415,490,415);
     line(426,416,489,416);

     line(425,449,490,449);
     line(426,448,489,448);

     line(490,415,490,449);
     line(489,416,489,448);

     arc(430,432,90,270,17);
     arc(430,432,90,270,16);

       setcolor(7);
     line(427,417,488,417);
     line(428,418,487,418);

     line(427,447,488,447);
     line(428,446,487,446);

     line(488,417,488,447);
     line(487,418,487,446);

     arc(430,432,90,270,15);
     arc(430,432,90,270,14);

       setcolor(8);
     line(429,419,486,419);
     line(429,445,486,445);
     line(486,419,486,445);

     arc(430,432,90,270,13);

       setcolor(9);
       setfillstyle(1,9);
     bar(430,420,485,444);

     pieslice(430,432,0,360,12);

       settextstyle(2,0,6);
     setcolor(0);
       outtextxy(433,422,"Exit");
       outtextxy(434,422,"Exit");

     setcolor(14);
       outtextxy(435,420,"Exit");
       outtextxy(436,420,"Exit");

       setcolor(15);
       settextstyle(0,0,1);
     outtextxy(30,425,"* Copyright  (C) 2000-01");
     outtextxy(30,440,"* Muhammad Tahir Shahzad");

       int count_5=0;
       int key_code=0;

       char key='\0';

       do
     {
         delay(500);

         key='\0';
         key_code=0;

         if(kbhit( ))
        key=getch( );

         key_code=int(key);

         if(count_5%2==0)
        {
           settextstyle(0,0,1);
             setcolor(1);
               outtextxy(435,400,"<Esc>");

             setcolor(4);
               outtextxy(515,400,"<Enter>");
        }

         elseif(count_5%2==1)
        {
           settextstyle(0,0,1);
             setcolor(4);
               outtextxy(435,400,"<Esc>");

             setcolor(1);
               outtextxy(515,400,"<Enter>");
        }

         count_5++;
     }
       while(key_code!=13 && key_code!=27);

       if(key_code==13)
      {
         settextstyle(0,0,1);
           setcolor(1);
         outtextxy(435,400,"<Esc>");

           setcolor(4);
         outtextxy(515,400,"<Enter>");

         setcolor(12);
         setfillstyle(1,12);
           bar(500,420,580,444);

           pieslice(580,432,0,360,12);

         settextstyle(2,0,6);
           setcolor(0);
         outtextxy(508,422,"Evaluate");
         outtextxy(509,422,"Evaluate");

           setcolor(14);
         outtextxy(510,420,"Evaluate");
         outtextxy(511,420,"Evaluate");

         delay(500);

         setcolor(9);
         setfillstyle(1,9);
           bar(500,420,580,444);

           pieslice(580,432,0,360,12);

         settextstyle(2,0,6);
           setcolor(0);
         outtextxy(508,422,"Evaluate");
         outtextxy(509,422,"Evaluate");

           setcolor(14);
         outtextxy(510,420,"Evaluate");
         outtextxy(511,420,"Evaluate");
      }

       elseif(key_code==27)
      {
         settextstyle(0,0,1);
           setcolor(4);
         outtextxy(435,400,"<Esc>");

           setcolor(1);
         outtextxy(515,400,"<Enter>");

         setcolor(12);
         setfillstyle(1,12);
           bar(430,420,485,444);

           pieslice(430,432,0,360,12);

         settextstyle(2,0,6);
           setcolor(0);
         outtextxy(433,422,"Exit");
         outtextxy(434,422,"Exit");

           setcolor(14);
         outtextxy(435,420,"Exit");
         outtextxy(436,420,"Exit");

         delay(500);

         setcolor(9);
         setfillstyle(1,9);
           bar(430,420,485,444);

           pieslice(430,432,0,360,12);

         settextstyle(2,0,6);
           setcolor(0);
         outtextxy(433,422,"Exit");
         outtextxy(434,422,"Exit");

           setcolor(14);
         outtextxy(435,420,"Exit");
         outtextxy(436,420,"Exit");

         delay(500);
         exit(0);
      }

       delay(500);
       cleardevice( );
    }

 /*************************************************************************///-----------------------  get_infix_expression( )  ---------------------///*************************************************************************/void Evaluator::get_infix_expression( )
    {
       setfillstyle(1,6);
     bar(0,0,getmaxx( ),getmaxy( ));

       setfillstyle(1,3);
     bar(5,5,getmaxx( )-5,getmaxy( )-5);

       setfillstyle(6,1);
     bar(10,10,getmaxx( )-10,getmaxy( )-10);

       for(int count_1=0;count_1<3;count_1++)
      {
         setcolor(1);
           settextstyle(4,0,10);
         outtextxy(20-count_1,50-count_1,"+");
         outtextxy(420-count_1,20,"^");
         outtextxy(100-count_1,150,"*");
         outtextxy(550-count_1,100-count_1,"-");
         outtextxy(320-count_1,20,"/");
         outtextxy(250-count_1,140,"(");
         outtextxy(500-count_1,250,")");

           settextstyle(1,0,10);
         outtextxy(70-count_1,320,"0");
         outtextxy(550-count_1,-20,"1");
         outtextxy(150-count_1,100,"2");
         outtextxy(450-count_1,100,"3");
         outtextxy(220-count_1,-20,"4");
         outtextxy(570-count_1,220,"5");
         outtextxy(360-count_1,170,"6");
         outtextxy(200-count_1,335,"7");
         outtextxy(20-count_1,-10,"8");
         outtextxy(400-count_1,320,"9");
      }

       settextstyle(1,0,4);
     setcolor(0);
       outtextxy(150,52,"Arithmetic");
       outtextxy(151,52,"Arithmetic");

     setcolor(12);
       outtextxy(152,50,"Arithmetic");
       outtextxy(153,50,"Arithmetic");

       settextstyle(1,0,8);
     setcolor(0);
       outtextxy(77,52,"Expression");
       outtextxy(78,52,"Expression");
       outtextxy(79,52,"Expression");

     setcolor(12);
       outtextxy(80,50,"Expression");
       outtextxy(81,50,"Expression");
       outtextxy(82,50,"Expression");
       outtextxy(83,50,"Expression");

       settextstyle(1,0,8);
     setcolor(0);
       outtextxy(217,122,"Evaluator");
       outtextxy(218,122,"Evaluator");
       outtextxy(219,122,"Evaluator");

     setcolor(12);
       outtextxy(220,120,"Evaluator");
       outtextxy(221,120,"Evaluator");
       outtextxy(222,120,"Evaluator");
       outtextxy(223,120,"Evaluator");

       settextstyle(6,0,4);
     setcolor(8);
       outtextxy(28,262,"Enter the Infix Expression :");
       outtextxy(29,262,"Enter the Infix Expression :");

     setcolor(10);
       outtextxy(30,260,"Enter the Infix Expression :");
       outtextxy(31,260,"Enter the Infix Expression :");
       outtextxy(32,260,"Enter the Infix Expression :");

       setcolor(15);
     rectangle(29,305,595,375);
     rectangle(30,306,594,374);

       setcolor(7);
     rectangle(31,307,593,373);
     rectangle(32,308,592,372);
     rectangle(33,309,591,371);

       setcolor(8);
     rectangle(34,310,590,370);

       setfillstyle(1,0);
     bar(35,311,589,369);

       int flag=0;
       int count_2=-1;
       int number_length=0;
       int operand_count=0;
       int operator_count=0;
       int expression_right_wrong=1;
       int left_parenthesis_count=0;
       int right_parenthesis_count=0;

       do
      {
         set_initial_values( );

         flag=0;
         count_2=-1;
         number_length=0;
         operand_count=0;
         operator_count=0;
         input_characters_count=0;
         expression_right_wrong=1;
         left_parenthesis_count=0;
         right_parenthesis_count=0;

         do
        {
           if(infix_expression[0][0]=='\0')
              {
             while(!kbhit( ))
                {
                   setcolor(14);
                   settextstyle(1,0,4);
                 outtextxy(40,313,"Þ");
                 outtextxy(40,327,"Þ");

                   delay(250);

                   setfillstyle(0,0);
                 bar(35,311,589,369);

                   delay(300);
                }
              }

           char temp_expression[2]={'\0'};

           temp_expression[0]=getch( );

           if( (int(temp_expression[0])>=48 &&
                int(temp_expression[0])<=57) && number_length<5 )
              {
             if(flag==0)
                {
                   count_2++;
                   strcpy(infix_expression[count_2],
                                temp_expression);
                   flag=1;
                   operand_count++;
                }

             elseif(flag==1)
                strcat(infix_expression[count_2],temp_expression);

             number_length++;
              }

           elseif( temp_expression[0]=='^' || temp_expression[0]=='/'
             || temp_expression[0]=='*' || temp_expression[0]=='-'
             || temp_expression[0]=='+' || temp_expression[0]=='('
                           || temp_expression[0]==')')
              {
             count_2++;

             strcpy(infix_expression[count_2],temp_expression);

             flag=0;
             number_length=0;

             if(temp_expression[0]=='(')
                left_parenthesis_count++;

             if(temp_expression[0]==')')
                right_parenthesis_count++;

             if(temp_expression[0]!='(' &&
                             temp_expression[0]!=')')
                operator_count++;
              }

           if(int(temp_expression[0])==8 && count_2>=0)
              {
             setfillstyle(1,0);
               bar(35,311,589,369);

             if(int(infix_expression[count_2][0])>=48 &&
                       int(infix_expression[count_2][0])<=57)
                operand_count--;

             if(infix_expression[count_2][0]=='^' ||
                   infix_expression[count_2][0]=='/' ||
                  infix_expression[count_2][0]=='*' ||
                     infix_expression[count_2][0]=='-' ||
                    infix_expression[count_2][0]=='+' )
                operator_count--;

             if(infix_expression[count_2][0]=='(')
                left_parenthesis_count--;

             if(infix_expression[count_2][0]==')')
                right_parenthesis_count--;

             for(int count_3=0;count_3<6;count_3++)

             strset(infix_expression[count_2],NULL);

             count_2--;
             input_characters_count--;
             flag=0;
              }

           if(int(temp_expression[0])==13)
              break;

           if(int(temp_expression[0])==27)
              {
             infix_expression[25][6]='$';
             break;
              }

           if(operand_count<operator_count)
              {
             infix_expression[25][6]='$';
             break;
              }

           if(!left_parenthesis_count && right_parenthesis_count)
              {
             count_2++;
             break;
              }

           if(temp_expression[0]!='^' && temp_expression[0]!='/' &&
              temp_expression[0]!='*' && temp_expression[0]!='-' &&
              temp_expression[0]!='(' && temp_expression[0]!=')' &&
              temp_expression[0]!='+' && temp_expression[0]!='0' &&
              temp_expression[0]!='1' && temp_expression[0]!='2' &&
              temp_expression[0]!='3' && temp_expression[0]!='4' &&
              temp_expression[0]!='5' && temp_expression[0]!='6' &&
              temp_expression[0]!='7' && temp_expression[0]!='8' &&
              temp_expression[0]!='9' && int(temp_expression[0])!=8
                         && int(temp_expression[0])!=27 )
              {
             infix_expression[25][6]='$';
             break;
              }

           int x=45;
           int y=320;

           for(int count_4=0;count_4<=count_2;count_4++)
              {
             setcolor(14);
             settextstyle(1,0,4);

             moveto(x,y);
               outtext(infix_expression[count_4]);

             x=getx( );
              }

           input_characters_count++;
        }
         while(count_2<=22 && input_characters_count<=24);

         if(operator_count!=operand_count-1)
        expression_right_wrong=0;

         if(left_parenthesis_count!=right_parenthesis_count)
        expression_right_wrong=0;

         if(count_2<2)
        expression_right_wrong=0;

         if(infix_expression[25][6]=='$')
        expression_right_wrong=0;

         if(expression_right_wrong==0)
        {
           setfillstyle(1,0);
             bar(35,311,589,369);

           setcolor(10);
           settextstyle(1,0,5);
             outtextxy(60,310,"Wrong Expression");

           sound(2500);
           delay(500);
           nosound( );

           setfillstyle(1,0);
             bar(35,311,589,369);
        }
      }
       while(!expression_right_wrong);

       if(input_characters_count==25)
      while(int(getch( ))!=13);

       infix_rows=count_2+1;

       cleardevice( );
    }

 /*************************************************************************///---------------------------  int_push( )  -----------------------------///*************************************************************************/void Evaluator::int_push(long item)
    {
       int_top++;
       int_stack[int_top]=item;
    }

 /*************************************************************************///---------------------------  int_pop( )  ------------------------------///*************************************************************************/long Evaluator::int_pop( )
    {
       long item=0;

       item=int_stack[int_top];
       int_stack[int_top]=0;
       int_top--;

       return item;
    }

 /*************************************************************************///--------------------------  char_push( )  -----------------------------///*************************************************************************/void Evaluator::char_push(char item)
    {
       char_top++;
       char_stack[char_top]=item;
    }

 /*************************************************************************///--------------------------  char_pop( )  ------------------------------///*************************************************************************/char Evaluator::char_pop( )
    {
       char item=0;

       item=char_stack[char_top];
       char_stack[char_top]='\0';
       char_top--;

       return item;
    }

 /*************************************************************************///----------------------  show_infix_screen( )  -------------------------///*************************************************************************/void Evaluator::show_infix_screen( )
    {
       setfillstyle(1,1);
     bar(0,0,getmaxx( ),getmaxy( ));

       setfillstyle(1,3);
     bar(5,5,getmaxx( )-5,getmaxy( )-5);

       setfillstyle(1,6);
     bar(10,10,getmaxx( )-10,getmaxy( )-10);

       setcolor(15);
     line(75,45,530,45);

       setcolor(7);
     line(75,46,530,46);
     line(75,47,530,47);
     line(75,48,530,48);

       setcolor(8);
     line(75,49,530,49);

       setcolor(0);
     line(75,50,530,50);

       settextstyle(2,0,8);
     setcolor(0);
       outtextxy(78,21,"Convertion from Infix to Postfix");
       outtextxy(79,21,"Convertion from Infix to Postfix");

     setcolor(3);
       outtextxy(80,20,"Convertion from Infix to Postfix");
       outtextxy(81,20,"Convertion from Infix to Postfix");
       outtextxy(82,20,"Convertion from Infix to Postfix");

       setcolor(10);
       settextstyle(2,0,7);
     outtextxy(20,65,"Infix Expression :");
     outtextxy(21,65,"Infix Expression :");

       setcolor(15);
     rectangle(18,88,287,127);

       setcolor(7);
     rectangle(20,90,285,125);
     rectangle(19,89,286,126);

       setfillstyle(1,0);
     bar(21,91,284,124);

       setcolor(8);
     rectangle(21,91,284,124);

       setcolor(15);
     line(55,217,255,217);
     line(55,253,255,253);

     arc(55,235,90,270,18);
     arc(255,235,270,90,18);

     rectangle(52,255,258,443);

       setcolor(7);
     line(55,218,255,218);
     line(55,219,255,219);

     line(55,251,255,251);
     line(55,252,255,252);

     arc(55,235,90,270,17);
     arc(55,235,90,270,16);

     arc(255,235,270,90,17);
     arc(255,235,270,90,16);

     rectangle(53,256,257,442);
     rectangle(54,257,256,441);

       setcolor(8);
     line(55,220,255,220);
     line(55,250,255,250);

     arc(55,235,90,270,15);
     arc(255,235,270,90,15);

     rectangle(55,258,255,440);

     setcolor(9);
     setfillstyle(1,9);
       bar(55,221,255,249);

       pieslice(55,235,0,360,14);
       pieslice(255,235,0,360,14);

       settextstyle(2,0,8);
     setcolor(0);
       outtextxy(77,221,"Explanation");
       outtextxy(78,221,"Explanation");

     setcolor(14);
       outtextxy(79,220,"Explanation");
       outtextxy(80,220,"Explanation");
       outtextxy(81,220,"Explanation");

       setfillstyle(1,0);
     bar(56,259,254,439);

       setcolor(8);
     line(183,404,220,404);
     line(183,430,220,430);

     line(183,404,183,430);

     arc(220,417,270,90,13);

       setcolor(7);
     line(184,405,220,405);
     line(185,406,220,406);

     line(184,429,220,429);
     line(185,428,220,428);

     line(184,405,184,429);
     line(185,406,185,428);

     arc(220,417,270,90,12);
     arc(220,417,270,90,11);

       setcolor(8);
     line(186,407,220,407);
     line(186,427,220,427);
     line(186,407,186,427);

     arc(220,417,270,90,10);

       setcolor(9);
       setfillstyle(1,9);
     bar(187,408,220,426);

     pieslice(220,417,0,360,9);

       settextstyle(2,0,5);
     setcolor(0);
       outtextxy(189,409,"Next>");
       outtextxy(190,409,"Next>");

     setcolor(14);
       outtextxy(191,408,"Next>");
       outtextxy(192,408,"Next>");

       setfillstyle(1,0);
     bar(295,88,620,460);

       setcolor(15);
     rectangle(295,88,620,460);

       setcolor(7);
     rectangle(296,89,619,459);
     rectangle(297,90,618,458);
     rectangle(298,91,617,457);

       setcolor(8);
     rectangle(299,92,616,456);

       setfillstyle(1,9);
     bar(300,92,615,119);

       setcolor(15);
     line(300,120,615,120);

       setcolor(7);
     line(300,121,615,121);
     line(300,122,615,122);

       setcolor(8);
     line(300,123,615,123);

       setcolor(15);
     line(367,92,367,456);

       setcolor(7);
     line(368,92,368,456);
     line(369,92,369,456);

       setcolor(8);
     line(370,92,370,456);

       setcolor(15);
     line(442,92,442,456);

       setcolor(7);
     line(443,92,443,456);
     line(444,92,444,456);

       setcolor(8);
     line(445,92,445,456);

       settextstyle(2,0,5);
     setcolor(0);
       outtextxy(305,92,"Symbol");
       outtextxy(305,105,"Scanned");

       outtextxy(306,92,"Symbol");
       outtextxy(306,105,"Scanned");

     setcolor(14);
       outtextxy(306,91,"Symbol");
       outtextxy(306,104,"Scanned");

       outtextxy(307,91,"Symbol");
       outtextxy(307,104,"Scanned");

       settextstyle(2,0,7);
     setcolor(0);
       outtextxy(375,96,"STACK");
       outtextxy(376,96,"STACK");

     setcolor(14);
       outtextxy(377,95,"STACK");
       outtextxy(378,95,"STACK");

     setcolor(0);
       outtextxy(459,96,"Expression P");
       outtextxy(459,96,"Expression P");

     setcolor(14);
       outtextxy(460,95,"Expression P");
       outtextxy(461,95,"Expression P");

       settextstyle(2,0,4);
     setcolor(15);
       outtextxy(20,447,"Note : If you don't want to see explanation,");
       outtextxy(60,459,"Press <Esc> , else Press any Key.");

     setcolor(10);
       outtextxy(20,447,"Note :");
       outtextxy(21,447,"Note :");
    }

 /*************************************************************************///-----------------  show_infix_to_postfix_convertion( )  ---------------///*************************************************************************/void Evaluator::show_infix_to_postfix_convertion( )
    {
       show_infix_screen( );

       int x_1=30;
       int y_1=97;
       int color_array[7]={3,6,5,10,11,14,12};

       for(int count_1=0;count_1<=infix_rows;count_1++)
     {
        settextstyle(2,0,6);
        setcolor(color_array[count_1%7]);

          moveto(x_1-1,y_1);
        outtext(infix_expression[count_1]);

          moveto(x_1,y_1);
        outtext(infix_expression[count_1]);

        x_1=getx( );
     }

       char_push('(');
       strcpy(infix_expression[infix_rows],")");

       int count_2=0;
       int count_3=0;
       int explain_yes_not=0;

       do
      {
         char symbol_scanned[6]={'\0'};
         char step_number[5]={'\0'};

         strcpy(symbol_scanned,infix_expression[count_2]);

         itoa(count_2+1,step_number,10);
         strcat(step_number,".");

         if(symbol_scanned[0]=='(')
        {
           char_push(symbol_scanned[0]);

           if(explain_yes_not==0)
              show_explanation(2);
        }

         elseif(symbol_scanned[0]==')')
        {
           char temp[2]={'\0'};

           while(char_stack[char_top]!='(')
              {
             temp[0]='\0';
             temp[0]=char_pop( );

             strcpy(postfix_expression[count_3],temp);

             count_3++;
              }

            temp[0]=char_pop( );

            if(explain_yes_not==0)
               show_explanation(3);
        }

         elseif(symbol_scanned[0]=='/' || symbol_scanned[0]=='*' ||
               symbol_scanned[0]=='-' || symbol_scanned[0]=='+'
                           || symbol_scanned[0]=='^')
        {
           if(symbol_scanned[0]=='^')
              {
              }

           elseif(symbol_scanned[0]=='*' || symbol_scanned[0]=='/')
              {
             while(char_stack[char_top]=='^' ||
                    char_stack[char_top]=='*' ||
                           char_stack[char_top]=='/')
                {
                char temp[2]={'\0'};

                temp[0]=char_pop( );
                strcpy(postfix_expression[count_3],temp);

                count_3++;
                }
              }

           elseif(symbol_scanned[0]=='+' || symbol_scanned[0]=='-')
              {
             while(char_stack[char_top]!='(')
                {
                char temp[2]={'\0'};

                temp[0]=char_pop( );
                strcpy(postfix_expression[count_3],temp);

                count_3++;
                 }
              }

           char_push(symbol_scanned[0]);

           if(explain_yes_not==0)
              show_explanation(4);
        }

         elseif(symbol_scanned[0]!='/' || symbol_scanned[0]!='*' ||
             symbol_scanned[0]!='-' || symbol_scanned[0]!='+' ||
             symbol_scanned[0]!='(' || symbol_scanned[0]!=')' ||
                              symbol_scanned[0]!='^')
        {
           strcpy(postfix_expression[count_3],symbol_scanned);

           if(explain_yes_not==0)
              show_explanation(1);

           count_3++;
        }

         if(infix_rows>16 || input_characters_count>20)
        {
           settextstyle(2,0,4);
             setcolor(15);
               outtextxy(302,130+(12*count_2),step_number);

             setcolor(14);
               outtextxy(328,130+(12*count_2),symbol_scanned);
        }

         else
        {
           settextstyle(0,0,1);
             setcolor(15);
               outtextxy(302,130+(14*count_2),step_number);

             setcolor(14);
               outtextxy(328,130+(14*count_2),symbol_scanned);
        }

         int x_2=450;
         int y_2;

         if(infix_rows>16 || input_characters_count>20)
        {
           y_2=130+(count_2*12);

           settextstyle(2,0,4);
        }

         else
        {
           y_2=130+(count_2*14);

           settextstyle(0,0,1);
        }

         for(int count_4=0;count_4<count_3;count_4++)
        {
           setcolor(color_array[count_4%7]);

           moveto(x_2,y_2);
             outtext(postfix_expression[count_4]);

           x_2=getx( );
        }

         show_char_stack(count_2);

         count_2++;

         char key='\0';

         int key_code=0;

         if(explain_yes_not==0)
        {
           key=getch( );
           key_code=int(key);

           if(key_code==27)
              explain_yes_not=1;
        }

         else
        delay(200);

      }
       while(char_stack[char_top]!='\0');

       show_explanation(8);

       while(int(getch( ))!=13);

       postfix_rows=count_3;

    }

 /*************************************************************************///--------------------------  show_explanation(int)  --------------------///*************************************************************************/void Evaluator::show_explanation(int flag)
    {
       setcolor(12);
       setfillstyle(1,12);
     bar(187,408,220,426);

     pieslice(220,417,0,360,9);

       settextstyle(2,0,5);
     setcolor(0);
       outtextxy(189,409,"Next>");
       outtextxy(190,409,"Next>");

     setcolor(14);
       outtextxy(191,408,"Next>");
       outtextxy(192,408,"Next>");

       delay(500);

       setfillstyle(1,0);
     bar(56,259,254,395);

       setcolor(15);
       settextstyle(2,0,4);

       if(flag==0)
      {
         outtextxy(60,263,"  The scanned symnol");
         outtextxy(60,278,"is an operand, so it");
         outtextxy(60,293,"will be pushed onto ");
         outtextxy(60,308,"the stack.");
      }

       elseif(flag==1)
      {
         outtextxy(60,263,"    The scanned symnol is an");
         outtextxy(60,278,"operand, so it is added to the");
         outtextxy(60,293,"Postfix Expression 'P'. ");
      }

       elseif(flag==2)
      {
         outtextxy(60,263,"    The scanned symbol is the");
         outtextxy(60,278,"left parenthesis '(', so it is");
         outtextxy(60,293,"pushed onto the Stack straight");
         outtextxy(60,308,"away.");
      }

       elseif(flag==3)
      {
         outtextxy(60,262,"    The scanned symbol is an");
         outtextxy(60,277,"right parenthesis ')', so the");
         outtextxy(60,292,"operators from the top of the");
         outtextxy(60,307,"Stack are Poped & added to the");
         outtextxy(60,322,"Postfix Expression 'P' until the");
         outtextxy(60,337,"left parenthesis '(' occured.");
         outtextxy(60,352,"   The left parenthesis '(' is");
         outtextxy(60,367,"also Poped from the Stack.");
      }

       elseif(flag==4)
      {
         outtextxy(60,262,"      The scanned symbol is an");
         outtextxy(60,275,"operator, so the operator on the");
         outtextxy(60,288,"top of the Stack are Poped and");
         outtextxy(60,301,"added to the Postfix Expression");
         outtextxy(60,314,"'P' until the operator on the top");
         outtextxy(60,327,"of the Stack has more or equal");
         outtextxy(60,340,"precedence then the scanned");
         outtextxy(60,353,"operator (if any).");
         outtextxy(60,366,"    Finally, the scanned operator");
         outtextxy(60,379,"is Pushed onto the Stack.");
      }

       elseif(flag==5)
      {
         outtextxy(60,262,"    The scanned symnol is an");
         outtextxy(60,277,"operand, so it is Pushed onto");
         outtextxy(60,292,"the Stack. ");
      }

       elseif(flag==6)
      {
         outtextxy(60,262,"    The scanned symbol is an");
         outtextxy(60,277,"operator, so two values from the");
         outtextxy(60,292,"top of the Stack are Poped and");
         outtextxy(60,307,"their result, attained by mani-");
         outtextxy(60,322,"pluating the Poped values & the");
         outtextxy(60,337,"scanned operator, is Pushed onto");
         outtextxy(60,352,"the Stack.");
      }

       elseif(flag==7)
      {
         outtextxy(60,262,"    The scanned symnol is the");
         outtextxy(60,277,"equal sign, so that is end of");
         outtextxy(60,292,"the evaluation of the Expression");
         outtextxy(60,307,"'P' and the value on the top of ");
         outtextxy(60,322,"Stack is our Result.");
      }
       elseif(flag==8)
      {
         outtextxy(60,262,"     This is the end of the");
         outtextxy(60,277,"convertion of Infix Expression");
         outtextxy(60,292,"into the Postfix Expression.");
      }


       setcolor(9);
       setfillstyle(1,9);
     bar(187,408,220,426);

     pieslice(220,417,0,360,9);

       settextstyle(2,0,5);
     setcolor(0);
       outtextxy(189,409,"Next>");
       outtextxy(190,409,"Next>");

     setcolor(14);
       outtextxy(191,408,"Next>");
       outtextxy(192,408,"Next>");
    }

 /*************************************************************************///------------------------  show_postfix_screen( )  ---------------------///*************************************************************************/void Evaluator::show_postfix_screen( )
    {
       setfillstyle(1,6);
     bar(75,25,530,45);

       settextstyle(2,0,8);
     setcolor(0);
       outtextxy(76,21,"Evaluation of Postfix Expression");
       outtextxy(77,21,"Evaluation of Postfix Expression");

     setcolor(3);
       outtextxy(78,20,"Evaluation of Postfix Expression");
       outtextxy(79,20,"Evaluation of Postfix Expression");
       outtextxy(80,20,"Evaluation of Postfix Expression");

       setcolor(15);
     rectangle(18,158,287,197);

       setcolor(7);
     rectangle(20,160,285,195);
     rectangle(19,159,286,196);

       setfillstyle(1,0);
     bar(21,161,284,194);

       setcolor(8);
     rectangle(21,161,284,194);

       setcolor(10);
       settextstyle(2,0,7);
     outtextxy(20,135,"Postfix Expression :");
     outtextxy(21,135,"Postfix Expression :");

       int color_array[7]={3,6,5,10,11,14,12};
       int x=30;

       for(int count_1=0;count_1<=postfix_rows;count_1++)
      {
         settextstyle(2,0,6);
         setcolor(color_array[count_1%7]);

           moveto(x-1,167);
         outtext(postfix_expression[count_1]);

           moveto(x,167);
         outtext(postfix_expression[count_1]);

         x=getx( );
     }

       setfillstyle(1,0);
     bar(295,88,620,460);

       setcolor(15);
     rectangle(295,88,620,460);

       setcolor(7);
     rectangle(296,89,619,459);
     rectangle(297,90,618,458);
     rectangle(298,91,617,457);

       setcolor(8);
     rectangle(299,92,616,456);

       setfillstyle(1,9);
     bar(300,92,615,119);

       setcolor(15);
     line(300,120,615,120);

       setcolor(7);
     line(300,121,615,121);
     line(300,122,615,122);

       setcolor(8);
     line(300,123,615,123);

       setcolor(15);
     line(387,92,387,456);

       setcolor(7);
     line(388,92,388,456);
     line(389,92,389,456);

       setcolor(8);
     line(390,92,390,456);

       settextstyle(2,0,5);
     setcolor(0);
       outtextxy(303,92,"Symbol");
       outtextxy(318,105,"Scanned");

       outtextxy(304,92,"Symbol");
       outtextxy(319,105,"Scanned");

     setcolor(14);
       outtextxy(305,91,"Symbol");
       outtextxy(320,104,"Scanned");

       outtextxy(306,91,"Symbol");
       outtextxy(321,104,"Scanned");

       settextstyle(2,0,7);
     setcolor(0);
       outtextxy(473,96,"STACK");
       outtextxy(474,96,"STACK");

     setcolor(14);
       outtextxy(475,95,"STACK");
       outtextxy(476,95,"STACK");
       outtextxy(477,95,"STACK");
    }

 /*************************************************************************///------------  show_evaluation_of_postfix_expression( )  ---------------///*************************************************************************/void Evaluator::show_evaluation_of_postfix_expression( )
    {
       show_postfix_screen( );

       int count_1=0;
       int explain_yes_not=0;

       char symbol_scanned[6]={'\0'};

       strcat(postfix_expression[postfix_rows],"=");

       do
      {
         for(int count_2=0;count_2<6;count_2++)
        symbol_scanned[count_2]='\0';

         strcpy(symbol_scanned,postfix_expression[count_1]);

         count_1++;

         char step_number[5]={'\0'};

         itoa(count_1,step_number,10);
         strcat(step_number,".");

         setcolor(15);
         settextstyle(0,0,1);
        outtextxy(305,120+(15*count_1),step_number);

         setcolor(14);
        outtextxy(335,120+(15*count_1),symbol_scanned);

         if(symbol_scanned[0]=='/' || symbol_scanned[0]=='*' ||
        symbol_scanned[0]=='-' || symbol_scanned[0]=='+' ||
                             symbol_scanned[0]=='^')
        {
           long value_1=0;
           long value_2=0;
           long result=0;

           value_1=int_pop( );
           value_2=int_pop( );

           switch(symbol_scanned[0])
              {
             case'+': result=value_2+value_1;
                   break;

             case'/': result=value_2/value_1;
                   break;

             case'*': result=value_2*value_1;
                   break;

             case'-': result=value_2-value_1;
                   break;

             case'^': result=powl(value_2,value_1);
                   break;
              }

           int_push(result);

           if(explain_yes_not==0)
              show_explanation(6);
        }

         elseif((symbol_scanned[0]!='/' || symbol_scanned[0]!='*' ||
              symbol_scanned[0]!='-' || symbol_scanned[0]!='+' ||
               symbol_scanned[0]!='^' )&& symbol_scanned[0]!='=')

        {
           long number=atol(symbol_scanned);

           int_push(number);

           if(explain_yes_not==0)
              show_explanation(5);
        }

         show_int_stack(count_1);

         char key='\0';

         int key_code=0;

         if(explain_yes_not==0)
        {
           key=getch( );
           key_code=int(key);

           if(key_code==27)
              explain_yes_not=1;
        }

         else
        delay(200);

      }
       while(symbol_scanned[0]!='=');

       show_explanation(7);

       while(int(getch( ))!=13);
     }

 /*************************************************************************///-------------------------  show_char_stack(int)  ----------------------///*************************************************************************/void Evaluator::show_char_stack(int element_number)
    {
       char stack[25]={'\0'};

       for(int count=0;count<=char_top;count++)
      {
         char temp_stack[2]={'\0'};

         temp_stack[0]=char_stack[count];

         strcat(stack,temp_stack);
      }

       setcolor(11);

       if(infix_rows>16 || input_characters_count>20)
      {
         settextstyle(2,0,4);
           outtextxy(375,130+(12*element_number),stack);
      }

       else
      {
         settextstyle(0,0,1);
           outtextxy(375,130+(14*element_number),stack);
      }
    }

 /*************************************************************************///--------------------------  show_int_stack(int)  ----------------------///*************************************************************************/void Evaluator::show_int_stack(int element_number)
    {
       char stack[10][10]={'\0'};

       for(int count_1=0;count_1<10;count_1++)
      ltoa(int_stack[count_1],stack[count_1],10);

       int color_array[7]={3,6,5,10,11,14,12};
       int x_2=400;
       int y_2=120+(element_number*15);

       for(int count_2=0;count_2<=int_top;count_2++)
      {
         settextstyle(0,0,1);
         setcolor(color_array[count_2%7]);

           moveto(x_2,y_2);
         outtext(stack[count_2]);

         x_2=getx( );
      }
    }

 /*************************************************************************///--------------------------  show_summary( )  --------------------------///*************************************************************************/void Evaluator::show_summary( )
    {
       cleardevice( );

       setfillstyle(6,1);
       bar(5,5,getmaxx( )-5,getmaxy( )-5);

    for(int count_1=0;count_1<15;count_1++)
       {
          setcolor(count_1);
          rectangle(5+count_1,5+count_1,getmaxx( )-5-count_1,
                               getmaxy( )-5-count_1);
       }

       setfillstyle(1,14);
     bar(180,75,450,78);

       settextstyle(1,0,6);
     setcolor(0);
       outtextxy(138,20,"* Summary *");
       outtextxy(139,20,"* Summary *");

     setcolor(12);
       outtextxy(140,20,"* Summary *");
       outtextxy(141,20,"* Summary *");
       outtextxy(142,20,"* Summary *");

       settextstyle(1,0,4);
     setcolor(0);
       outtextxy(98,106,"Infix Expression :");
       outtextxy(99,106,"Infix Expression :");

     setcolor(10);
       outtextxy(100,105,"Infix Expression :");
       outtextxy(101,105,"Infix Expression :");

       setcolor(15);
     rectangle(99,145,501,200);
     rectangle(100,146,500,199);

       setcolor(7);
     rectangle(101,147,499,198);
     rectangle(102,148,498,197);

       setcolor(8);
     rectangle(103,149,497,196);
     rectangle(104,150,496,195);

       setfillstyle(1,0);
     bar(105,151,495,194);

       settextstyle(1,0,4);
     setcolor(0);
       outtextxy(98,220,"Postfix Expression :");
       outtextxy(99,220,"Postfix Expression :");

     setcolor(10);
       outtextxy(100,219,"Postfix Expression :");
       outtextxy(101,219,"Postfix Expression :");

       setcolor(15);
     rectangle(99,259,501,316);
     rectangle(100,260,500,315);

       setcolor(7);
     rectangle(101,261,499,314);
     rectangle(102,262,498,313);

       setcolor(8);
     rectangle(103,263,497,312);
     rectangle(104,264,496,311);

       setfillstyle(1,0);
     bar(105,265,495,310);

       settextstyle(1,0,5);
     setcolor(0);
       outtextxy(98,323,"Result :");
       outtextxy(99,323,"Result :");

     setcolor(10);
       outtextxy(100,322,"Result :");
       outtextxy(101,322,"Result :");

       setcolor(15);
     rectangle(99,369,501,431);
     rectangle(100,370,500,430);

       setcolor(7);
     rectangle(101,371,499,429);
     rectangle(102,372,498,428);

       setcolor(8);
     rectangle(103,373,497,427);
     rectangle(104,374,496,426);

       setfillstyle(1,0);
     bar(105,375,495,425);

       setcolor(11);
       settextstyle(2,0,8);

       int x_1=120;
       int y_1=157;

       for(int count_2=0;count_2<infix_rows;count_2++)
     {
        moveto(x_1-1,y_1);
          outtext(infix_expression[count_2]);

        moveto(x_1,y_1);
          outtext(infix_expression[count_2]);

        x_1=getx( );
     }

       int color_array[7]={3,6,5,10,11,14,12};
       int x_2=120;
       int y_2=270;

       for(int count_3=0;count_3<postfix_rows;count_3++)
     {
         settextstyle(2,0,8);
         setcolor(color_array[count_3%7]);

           moveto(x_2-1,y_2);
         outtext(postfix_expression[count_3]);

           moveto(x_2,y_2);
         outtext(postfix_expression[count_3]);

         x_2=getx( );
     }

       char result[10]={'\0'};

       ltoa(int_stack[0],result,10);

       setcolor(11);
       settextstyle(1,0,5);
     outtextxy(120,373,result);
     outtextxy(121,373,result);

       while(!getch( ));

       for(int count_4=0;count_4<320;count_4++)
      {
         setcolor(0);
           rectangle(getmaxx( )/2-count_4,getmaxy( )/2-count_4,
                  getmaxx( )/2+count_4,getmaxy( )/2+count_4);

         delay(1);
      }
    }

 int main( )
    {
       int driver=VGA;
       int mode=VGAHI;

       initgraph(&driver,&mode,"..\\Bgi");

       Evaluator obj;

       obj.show_main_screen( );
       obj.get_infix_expression( );
       obj.show_infix_to_postfix_convertion( );
       obj.show_evaluation_of_postfix_expression( );
       obj.show_summary( );

       closegraph( );

       return 0;
    }