c++ 函数指针做形参

求y=sqrt（x）的定积分

 

 

#include "stdafx.h"

#include <iostream>

#include <math.h>

using namespace std;

 

double fun(double x)

{

double y=sqrt(x);

return y;

}

double ans(double a,double b,double(*pt)(double x))

{

int i,n;

double step,sum=0;

n=(b/a)*10000;

step=(float)((b-a)/n);

for(i=1;i<=n;i++)

{

sum+=step*pt(a);

a+=step;

}

return sum;

}

 

 

int _tmain(int argc, _TCHAR* argv[])

{

double a,b,z;

cin>>a>>b;

z=ans(a,b,fun);

cout<<z<<endl;

return 0;

}