字符串判断大小 + 拼接

#include<bits/stdc++.h>
using namespace std;
int main(){
    string a,b,c;
    cin>>a>>b;
    if(a>b) c=a+b;
    else c=b+a;
    for(int i=1;i<c.length();i+=2){
        cout<<c[i];
    }
    return 0;
}