why we write int in overloading of postfix in c+ code example

Example: 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);"
};