C Program to implement Trapezoidal Rule

/*
 Trapezoidal Rule
 Equation: x/(1+x) dx
 lower limit=0  upper limit=1 number of interval=6
*/
#include<conio.h>
#include<stdio.h>
void main()
{
 float a,b,h,x,y,s=0;
 float x0,y0,xn,yn,r;
 int i,n;
 float f(float);
 clrscr();
 printf("\nEnter lower limit value:: ");
 scanf("%f",&a);
 printf("\nEnter upper limit value:: ");
 scanf("%f",&b);
 printf("\nEnter the number of intervals:: ");
 scanf("%d",&n);
 h=(b-a)/n;
 x0=a;
 y0=f(a);
 yn=f(b);
 x=x0+h;
 for(i=1;i<=n-1;i++)
 {
  y=f(x);
  s=s+y;
  x=x+h;
 }
 r=(h/2)*(y0+yn+2*s);
 printf("\nResult is:: %f",r);
 getch();
}
float f(float x)
{
 return x/(1+x);
}