prefix and postfix operator overloading in c++ code example

Example 1: prefix and postfix operator overloading in c++

struct X
{
    // prefix increment
    X& operator++()
    {
        // actual increment takes place here
        return *this; // return new value by reference
    }
 
    // postfix increment
    X operator++(int)
    {
        X old = *this; // copy old value
        operator++();  // prefix increment
        return old;    // return old value
    }
 
    // prefix decrement
    X& operator--()
    {
        // actual decrement takes place here
        return *this; // return new value by reference
    }
 
    // postfix decrement
    X operator--(int)
    {
        X old = *this; // copy old value
        operator--();  // prefix decrement
        return old;    // return old value
    }
};

Example 2: operator ++ overloading c++

class Point
{
public:
	Point& operator++() { ... }		// prefix
	Point operator++(int) { ... }	// postfix
  	friend Point& operator++(Point &p);			// friend prefix
  	friend Point operator++(Point &p, int);		// friend postfix
  	// in Microsoft Docs written "friend Point& operator++(Point &p, int);"
};