C programming for bisection method

/*bisection method*/

#include<stdio.h>

#include<math.h>

#define f(x) ((x*sin(x))+((x-2)*cos(x)))

void

main()

{

                int count;

                float a,b,x,y,y1,y2;

    printf("enter the valu of the intervals:");

                scanf("%f %f",&a,&b);

                y1=f(a);

                y2=f(b);

                count=1;

                if(y1*y2>0)

                                printf("\n invalid interval\n");

                                else

                                {label: x=(a+b)/2;

                                y=f(x);

                                if(y1*y<0)

                                {               b=x;

                                                y2=y;

                                }

                                else

                                {               a=x;

                                                y1=y;

                                }

                                printf("%d\t",count);

                                printf("%f\n",x);

                                count=count+1;

                                if(fabs(b-a)>0.001)

                                                goto label;

                                }

}

RESULT:

enter the valu of the intervals:2 5

1       3.500000

2       2.750000

3       3.125000

4       2.937500

5       2.843750

6       2.890625

7       2.867188

8       2.855469

9       2.849609

10      2.852539

11      2.851074

12      2.851807

Press any key to continue