#include <stdio.h>
#include <math.h>

void main()
{
    float integral(float(*)(float),float,float,int);
    float fsin(float);
    float fcos(float);
    float fexp(float);

    float a1,b1,a2,b2,a3,b3,c,(*p)(float);
    int n=20;

    printf("input a1,b1:");
    scanf("%f,%f",&a1,&b1);
    printf("input a2,b2:");
    scanf("%f,%f",&a2,&b2);
    printf("input a3,b3:");
    scanf("%f,%f",&a3,&b3);

    p=fsin;
    c=integral(p,a1,b1,n);
    printf("the integral of sin(x) is : %f\n",c);

    p=fcos;
    c=integral(p,a2,b2,n);
    printf("the integral of cos(x) is : %f\n",c);

    p=fexp;
    c=integral(p,a3,b3,n);
    printf("the integral of exp(x) is : %f\n",c);
}

float integral (float(*p)(float),float a,float b,float n)
{
    int i;
    float x,h,s;
    h=(b-a)/n;
    x=a;
    s=0;
    for(i=0;i<=n;i++)
    {
        x=x+h;
        s=s+(*p)(x)*h;
    }
    return(s);
}

float fsin(float x)
{return sin(x);}

float fcos(float x)
{return cos(x);}

float fexp(float x)
{return exp(x);}

顶一个

for(i=0;i<=n;i++)变为for(i=0;i<n;i++)；
float integral (float(*p)(float),float a,float b,float n) 变为 float integral (float(*p)(float),float a,float b,intn);

呵呵 谢谢