采用梯形法编程实现积分

#include <stdio.h>
float Fun1(float x);
float Fun2(float x);
float Integral(float (*f)(float), float a, float b);
int main()
{                            
    float y1, y2;
    y1 = Integral(Fun1, 0.0, 1.0);
    y2 = Integral(Fun2, 0.0, 3.0);
    printf("y1=%f\ny2=%f\n", y1, y2);
    return 0;
}                            
/*  函数功能：计算函数1+x*x的函数值 */
float Fun1(float x)
{                            
    return  1 + x * x;
}                            
/*  函数功能：计算函数x/(1+x*x)的函数值 */
float Fun2(float x)
{                            
    return x / (1 + x * x);
}                            
/*    函数功能：用梯形法计算函数的定积分 */
float Integral(float (*f)(float), float a, float b)
{                            
    float s, h;
    int n = 100, i;
    s = ((*f)(a) + (*f)(b)) / 2;
    h = (b - a) / n;
    for (i = 1; i < n; i++)
    {                            
        s += (*f)(a + i * h);
    }
    return s * h;
}