비교&관계 연산자 오버로딩

#pragma warning(disable : 4996)
 
#include <iostream>
#include <cstring>
 
using namespace std;
 
 
class String
{
private:
    char* _chars;
 
public:
    String(const char* chars)
        : _chars(new char[strlen(chars) + 1])
    {
        strcpy(_chars, chars);
    }
 
    bool operator==(const String& s) const 
    {
        return strcmp(_chars, s._chars) == 0;
    }
 
    bool operator!=(const String& s) const
    {
        return !(*this == s);
    }
 
    bool operator<(const String& s) const
    {
        return strcmp(_chars, s._chars) < 0;
    }
 
    bool operator>(const String& s) const
    {
        return strcmp(_chars, s._chars) > 0;
    }
 
    bool operator>=(const String& s) const
    {
        return !(*this < s);
    }
 
    bool operator<=(const String& s) const
    {
        return !(*this > s);
    }
 
    void print()
    {
        cout << _chars << endl;
    }
};
 
int main()
{
    // ==, !=, <, >, <=, >=, <=>
 
    String s0("abc");
    String s1("abd");
 
    if (s0 != s1)
        cout << "Eq" << endl;
 
    if (s0 < s1)
        cout << "Less" << endl;
}