cc22a_demo_c++重载自增自减操作符-代码示范

cc22a_demo_c++重载自增自减操作符-代码示范

#define  _CRT_SECURE_NO_WARNINGS
#include <iostream>
using namespace std;

class String
{
public:
    String(char const *chars="");
    String(String const &str);
    ~String();
    void display() const;
    String &operator++();//前加加  返回引用
    String const operator++(int);//后加加，返回拷贝
    String &operator--();
    String const operator--(int);
private:
    char *ptrChars;
};
String &String::operator++()
{
    for (std::size_t i = 0; i < std::strlen(ptrChars); ++i)
    {
        ++ptrChars[i];

    }
    return *this;
}
String const String::operator++(int n)  //int自动设置为0
{
    String copy(*this);
    ++(*this);
    return copy;
}
String::String(char const *chars)
{
    chars = chars ? chars : "";
    ptrChars = new char[std::strlen(chars)+1];
    std::strcpy(ptrChars,chars);
}
String::String(String const &str)
{
    ptrChars = new char[std::strlen(str.ptrChars) + 1];
    std::strcpy(ptrChars,str.ptrChars);
}
String::~String()
{
    delete[] ptrChars;
}
void String::display() const
{
    cout << ptrChars << endl;

}
int main()
{
    int x = 5;
    x++;
    ++x;
    //cout << x << endl;

    String s("ABC");
    s.display();
    ++s;
    s.display();
    ++s;
    s.display();
    cout << endl;

    String str1("ABC");
    str1.display();
    String str2(++str1);
    str2.display();
    String str3(str1++);
    
    
    str3.display();
    str1.display();
//    cout << "hello" << endl;
    system("pause");
    return 0;
}