麻烦帮我看下这个程序有啥问题，刚学c++不怎么会，谢谢

#include<iostream>
using namespace std;
int main(){
    char s1[20],s2[20];
    puts(s1);
    puts(s2);
        int r,i;
        for(i=0;s1[i]!='\0'&&s2[i]!='\0';i++){
            if (s1[i]>s2[i]){
                return r=1;
                cout<<"r= "<<r<<endl;
            }
            else if(s1[i]<s2[i]){
                return r=-1;
                cout<<"r= "<<r<<endl;
            }
            else
                continue;
    }
    if(s1[i]=='\0'&&s2[i]=='\0'){
        return r=0;
        cout<<"r= "<<r<<endl;
    }
    else if(s1[i]!='\0'&&s2[i]=='\0'){
        return r=1;
        cout<<"r= "<<r<<endl;
    }
    else
        return r=-1;
        cout<<"r= "<<r<<endl;
    return 0;


}