#include<stdio.h>
    #include<conio.h>
    #include<math.h>
    #define epsil 0.0001

    int p,c[10];
    
    void appro();
    void bisection(float,float,float,float);
    
    float fun(float x)
    {
    int i;
    float y=0.0;
    y=log10(x)-cos(x);
    return y;
    }

    void main()
    {
    int i;
    clrscr();
    appro();
    getch();
    }

    void bisection(float x1,float x2,float fx1,float fx2)
    {
    float x3,fx3;
    int n=1;
    if(fx1<0&&fx2>0||fx1>0&&fx2<0)
    {
    printf("******************************************************************\n");
    printf("\nIt   x1        fx1        x2         fx2        x3         fx3\n");
    printf("******************************************************************\n");
             do
             {
             x3=(x1+x2)/2;
             fx3=fun(x3);
             if(fx3==0)
             {
            break;
             }
             if((fx1*fx3)>0)
             {
             x1=x3;
             fx1=fx3;
             }
             else
             {
             x2=x3;
             fx2=fx3;
             }
             printf("%d   %.4f    %.4f     %.4f    %.4f    %.4f     %.4f\n",n,x1,fx1,x2,fx2,x3,fx3);
             n=n+1;
             }while((fabs(x1-x2)>epsil)&&(fx3!=0));
    printf("\n\t\t********************\n");
    printf("\n\t\tThe root is %.4f\n",x3);
    printf("\t\t********************\n");
    }
    else
    {
    clrscr();
    
    printf("\nError in the Initial approximation\n ");
    printf("\nPlease enter right approximation\n\n");
    appro();
    }
    }
    
    void appro()
    {
    float x1,x2,x3,fx1,fx2,fx3;
    printf("\nPlease Enter first approximation: ");
    scanf("%f",&x1);
    printf("\nPlease Enter first approximation: ");
    scanf("%f",&x2);
    fx1=fun(x1);
    fx2=fun(x2);
    bisection(x1,x2,fx1,fx2);
    }
    /*************************************OUTPUT**************************************

    Please Enter first approximation: 1

    Please Enter first approximation: 2
    ******************************************************************

    It   x1        fx1        x2         fx2        x3         fx3
    ******************************************************************
    1   1.0000    -0.5403     1.5000    0.1054    1.5000     0.1054
    2   1.2500    -0.2184     1.5000    0.1054    1.2500     -0.2184
    3   1.3750    -0.0562     1.5000    0.1054    1.3750     -0.0562
    4   1.3750    -0.0562     1.4375    0.0247    1.4375     0.0247
    5   1.4062    -0.0157     1.4375    0.0247    1.4062     -0.0157
    6   1.4062    -0.0157     1.4219    0.0045    1.4219     0.0045
    7   1.4141    -0.0056     1.4219    0.0045    1.4141     -0.0056
    8   1.4180    -0.0006     1.4219    0.0045    1.4180     -0.0006
    9   1.4180    -0.0006     1.4199    0.0020    1.4199     0.0020
    10   1.4180    -0.0006     1.4189    0.0007    1.4189     0.0007
    11   1.4180    -0.0006     1.4185    0.0001    1.4185     0.0001
    12   1.4182    -0.0003     1.4185    0.0001    1.4182     -0.0003
    13   1.4183    -0.0001     1.4185    0.0001    1.4183     -0.0001
    14   1.4184    -0.0000     1.4185    0.0001    1.4184     -0.0000

                        ********************
                           The root is 1.4184
                           ********************                            
    ************************************************************************/