C program to find real root of a equation using Bisection method

I am using equation f(x): x^³-2x-5 = x*x*x-2*x-5 (a=2 and b=3)
You can change it(x*x*x-2*x-5) to you own equation

Code:

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#include<stdio.h>
#include<conio.h>
# define eqn x*x*x-2*x-5

float f(float x)
{
   float ans;
   ans=eqn;
   return(ans);
}

void main()
{
   float a,b,x=0,x1=0;
   int i=0;
   clrscr();
   printf("Enter the a and b");
   scanf("%f%f",&a,&b);
   if(f(a)*f(b)>=0)
   {
      printf("The interval is wrong");
      getch();
      return;
   }
   do
   {
      x=(a+b)/2;
      printf("\ta=%f\tb=%f\tX%d=%f\tf(x%d)=%f\n",a,b,i,x,i,f(x));
      if(x==x1)
      {
         printf("\n\nThe root is %f\n",x);
         break;
      }
      x1=x;
      i++;
      if(f(a)*f(x)<0)
         b=x;
      else
         a=x;
   }while(f(a)*f(b)<0);
   getch();
}

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