写一个求x的n次方的函数
#include <iostream.h>
double cf(double x,int n)
{
    double b=1;
    for(int a=1;a<=n;a++)
    {
        b=b*a;
        return b;
    }
}
void main()
{
    double x;int n;
    cout<<"请输入X和N的值"<<endl;
    cin>>x>>n;
    cout<<x<<"的"<<n<<"次方为:"<<cf(x,n)<<endl;
}

把return b移到外面...而且...这个函数好像也不是求方的函数啊...
应该是
#include <iostream.h>
double cf(double x,int n)
{
    double b=1;
    for(int a=1;a<=n;a++)
    {
        b=b*x;
    }
    return b;
}
void main()
{
    double x;int n;
    cout<<"请输入X和N的值"<<endl;
    cin>>x>>n;
    cout<<x<<"的"<<n<<"次方为:"<<cf(x,n)<<endl;
}

#include <iostream.h>

double cf(double x, int n)
{
    double  b = 0;
    double  nI  = x;

    for(int a = 1;a <= n; a++)
    {
        x =  a * x * nI/a;
        b = x / nI;
    }
    
    return b;
}
void main()
{
    double x; int n;
    cout<<"请输入X和N的值"<<endl;
    cin>>x>>n;
    cout<<x<<"的"<<n<<"次方为:"<<cf(x,n)<<endl;
}


你试下这个函数