User-Defined Functions

Calculation of Area under a Curve

#include <stdio.h>
float start_point,end_point,total_area;
int numtraps;
void main()
{
void input(void);
float find_area(float a,float b,int n);
printf("AREA UNDER A CURVE");
input();
total_area=find_area(start_point,end_point,numtraps);
printf("TOTAL AREA = %f",total_area);
getch();
}
void input(void)
{
printf("\n Enter lower limit:");
scanf("%f",&start_point);
printf("Enter upper limit:");
scanf("%f",&end_point);
printf("Enter number of trapezoids:");
scanf("%d",&numtraps);
}
float find_area(float a,float b, int n)
{
float base,lower,h1,h2;
float function_x(float x);
float trap_area(float h1,float h2,float base);
base = (b-1)/n;
lower=a;
for(lower=a;lower<=b-base;lower=lower+base)
{
h1=function_x(lower);
h1=function_x(lower+base);
total_area+=trap_area(h1,h2,base);
}
return(total_area);
}
float trap_area(float height_1, float height_2,float base)
{
float area;
area=0.5*(height_1+height_2)*base;
return(area);
}
float function_x(float x)
{
return(x*x+1);
}