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

使用c++内置函数的多变量比较