#include
#include
using namespace std;
int main(){
float fsin( float x);
float fcos( float x);
float fe( float x);
float fpf(float x);
float fun(float a,float b, int n,float (*p)(float x));
float a[4],b[4],r[4];
cout<<"请输入求正弦函数定积分的上限a和下限b：";
cin>>a[0]>>b[0];
r[0]=fun(a[0],b[0],50,fsin);
cout<<"\n结果是："< cout<<"\n请输入求余弦函数定积分的上限a和下限b：";
cin>>a[1]>>b[1];
r[1]=fun(a[1],b[1],50,fcos);
cout<<"\n结果是："< cout<<"\n请输入求以e为底的指数函数定积分的上限a和下限b：";
cin>>a[2]>>b[2];
r[2]=fun(a[2],b[2],50,fe);
cout<<"\n结果是："< cout<<"\n请输入求X^2函数定积分的上限a和下限b：";
cin>>a[3]>>b[3];
r[3]=fun(a[3],b[3],50,fpf);
cout<<"\n结果是："< cout< return 0;
}
float fsin(float x){
return sin(x);
}
float fcos(float x){
return cos(x);
}
float fe(float x){
return exp(x);
}
float fpf(float x){
return pow(x,2);
}
float fun(float a,float b,int n,float (*p)(float x)){
float i;
float h=(b-a)/n;
float s=0;
for(i=a;i s=s+((p(i)+p(i+h))*h)/2;//梯形法求面积
}
return s;
}