求助vc++高手帮忙解决小问题

#include <iostream>
using namespace std;

double sortNum(double m,double n,double a)
{
        double tmp;
        if (n>a)
        {
            tmp=n;n=a;a=tmp;
        }
        if (m>n)
        {
            tmp=m;m=n;n=tmp;
        }   
        
        if (n>a)
        {
            tmp=n;n=a;a=n;
        }   
        

        cout<<"三个数的大小关系是:"<<m<<"<"<<n<<"<"<<a<<endl;
}


int main()
{
    cout<<"输入三个数："<<endl;
    double m,n,a;
    cin>>m>>n>>a;
    sortNum(m,n,a);
    return 0;
}

[ 本帖最后由 gz81 于 2009-9-25 15:23 编辑 ]