输入三个数，输出最大数，最小数

直接使用fmax()、fmin()函数即可

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int a,b,c;
    cin>>a>>b>>c;
    int max_num=fmax(a,fmax(b,c));
    int min_num=fmin(a,fmin(b,c));
    cout<<"The maximum number is : "<<max_num<<endl;
    cout<<"The minimum number is : "<<min_num<<endl;
}