C 中自定义类2种自增运算的代码实现和区别

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cpp i vs i for user defined class

Guide

code

#include 
#include 
#include 
#include 
#include 
using namespace std;

class Integer
{
public:
    Integer(int value): v(value)
    {
        cout << "default constructor" << endl;
    }
    Integer(const Integer &other)
    {
        cout << "copy constructor" << endl;
        v = other.v;
    }
    Integer &operator=(const Integer &other)
    {
        cout << "copy assignment" << endl;
        v = other.v;
        return *this;
    }

    //   i  first  1,then return new value
    Integer &operator  ()
    {
        cout << "Integer::operator  ()" << endl;
        v  ;
        return *this;
    }

    // i    first save old value,then  1,last return old value
    Integer operator  (int)
    {
        cout << "Integer::operator  (int)" << endl;
        Integer old = *this;
        v  ;
        return old;
    }

    void output()
    {
        cout << "value " << v << endl;
    }
private:
    int v;
};

void test_case()
{
    Integer obj(10);
    Integer obj2 = obj;
    Integer obj3(0);
    obj3 = obj;
    cout << "--------------" << endl;
    cout << "  i" << endl;
      obj;
    obj.output();
    cout << "i  " << endl;
    obj  ;
    obj.output();
}

int main()
{
    test_case();
    return 0;
}

output

    default constructor
    copy constructor
    default constructor
    copy assignment
    --------------
      i
    Integer::operator  ()
    value 11
    i  
    Integer::operator  (int)
    copy constructor
    value 12

Reference

• iplusplus_plusplusi

History

• 2019/11/08: created.

Copyright

• Post author: kezunlin
• Post link: https://kezunlin.me/post/caef83a3/
• Copyright Notice: All articles in this blog are licensed under CC BY-NC-SA 3.0 unless stating additionally.

Copyright

• Post author: kezunlin
• Post link: https://kezunlin.me/post/caef83a3/
• Copyright Notice: All articles in this blog are licensed under CC BY-NC-SA 3.0 unless stating additionally.