Write a C program to implement Trapezoidal method

 /*Write a C program to implement Trapezoidal method*/
#include<stdio.h>
#include<math.h>
float f(float);
float a; float b; float x; float h; float sum; int n; int i;
int main()
{
   clrscr();
   printf("Enter value for A:");
   scanf("%f",&a);
   printf("Enter value for B:");
   scanf("%f",&b);
   printf("Enter number of rectangles:");
   scanf("%d",&n);
   h=(b-a)/n;
   sum=(0.5*h)*(f(a)+f(b));
   printf("%f \n",sum);
   for(i=1;i<n;i++)
   {
     sum=sum+h*f(a+(i*h));
     printf("%f \n",sum);
   }
   printf("The value of the integral is:%f\n",sum);
getch();
}

float f(float x)
{
  float value;
  value=x*x+3;
  return value;
}

Output:

Enter value for A:25
Enter value for B:30
Enter number of rectangles:12
318.958313
589.377869
868.695007
1157.054321
1454.600586
1761.478516
2077.832764
2403.807861
2739.548584
3085.199707
3440.905762
3806.811523
The value of the integral is:3806.811523

Posted in: C