/* Trapezoid algorithm to approximate integral of F(x)=x+1 over [a,b] */
#include <stdio.h>
#include <math.h>
double Func(double x)
{
  return (x+1);
}
void main()
{
 double total, //total area of the interval
        h, // size of each sub-interval
       sum, // Value of approximation
       a,// left end
       b,// right end
       x;// variable

     int i,n;
     b=1.0;
     a=0.0;
     n=10;
     sum=0.5*(Func(a)+Func(b));
     h=(b-a)/n;
     for(i = 1; i<= n-1; i++)
     {
        x= a+i*h;
        sum=sum+Func(x); // Trapezoid rule formula
     }
     sum=h*sum;
    printf("Approximation is=%f\n", sum);
}