c++重载[]运算符

#include "iostream"
#include <string.h>
using namespace std;
class String{
public:
    char s[100];
    String(char str[]){
        strcpy(s, str);
    }
    char operator[](int a)const{
        return s[a];
    }
};
int main(){
    String a("abc");
    cout<<a.s<<endl;
    cout<<a[2]<<endl;
    return 0;
}

运行结果: