#include<stdio.h>
#include<conio.h>
#include<math.h>
void main()
{
  float mat[4][4],temp,temp1,x,y,z;
  int i,n,j;
  clrscr();
  printf("\nEnter size of matrix: ");
  scanf("%d",&n);
  for(i=0; i<n; i++)
  {
   printf("\n\nenter the value of %d eqvation",i+1);
   for(j=0; j<n; j++)
   {
    printf("\nenter the value of coeffcient %d: ",j+1);
    scanf("%f",&mat[i][j]);
   }
   printf("\nenter the value of constent: ");
   scanf("%f",&mat[i][j]);
  }

  printf("\n Your Matrix \n\n");
  for(i=0;i<n;i++)
  {
   for(j=0;j<n+1;j++)
   {
    printf(" %g ",mat[i][j]);
   }
   printf("\n\n");
  }

  temp=mat[1][0]/mat[0][0];
  temp1=mat[2][0]/mat[0][0];
  for(i=0,j=0;j<n+1;j++)
  {
   mat[i+1][j]=mat[i+1][j]-(mat[i][j]*temp);
   mat[i+2][j]=mat[i+2][j]-(mat[i][j]*temp1);
  }

  temp=mat[2][1]/mat[1][1];
  for(i=1,j=0;j<n+1;j++)
  {
   mat[i+1][j]=mat[i+1][j]-(mat[i][j]*temp);
  }


  for(i=0;i<n;i++)
  {
   for(j=0;j<n+1;j++)
   {
    printf(" %.3f ",mat[i][j]);
   }
   printf("\n\n");
  }

  z = mat[2][3]/mat[2][2];
  y = (mat[1][3] - mat[1][2]*z)/mat[1][1];
  x = (mat[0][3] - mat[0][2]*z - mat[0][1]*y)/mat[0][0];
  printf("\n\nx = %.3f",x);
  printf("\n\ny = %.3f",y);
  printf("\n\nz = %.3f",z);
  getch();
}


/*
______________________________________

         OUT PUT
______________________________________


enter the value of 1 eqvation
enter the value of coeffcient 1: 2

enter the value of coeffcient 2: 1

enter the value of coeffcient 3: 1

enter the value of constent: 10


enter the value of 2 eqvation
enter the value of coeffcient 1: 3

enter the value of coeffcient 2: 2

enter the value of coeffcient 3: 3

enter the value of constent: 18


enter the value of 3 eqvation
enter the value of coeffcient 1: 1

enter the value of coeffcient 2: 4

enter the value of coeffcient 3: 9

enter the value of constent: 16

  Your Matrix

 2  1  1  10

 3  2  3  18

 1  4  9  16

 2.000  1.000   1.000   10.000

 0.000  0.500   1.500   3.000

 0.000  0.000  -2.000  -10.000



x = 7.000

y = -9.000

z = 5.000


*/