Operator overloading

Class에 +,- 등의 연산자를 쓸 수 있게 하는 문법

#include <iostream> using namespace std; class overloading { public: int x; int y; overloading(int _x = 0, int _y = 0):x(_x),y(_y){} void Print() const { std::cout << x << ",\t" << y << std::endl;} overloading operator+(overloading& a) { return overloading(x+a.x, y+a.y); } overloading operator+(int a) { return overloading(x+a, y+a); } bool operator==(const overloading& a) { return( (x==a.x)&&(y==a.y) ); } // ++this const overloading& operator++() { x++; y++; return *this; } // this++ const overloading& operator++(int) { overloading temp(x, y); x++; y++; return temp; } // this() void operator()() { Print(); } // this[index] int operator[](int idx) { if( idx == 0) {std::cout << " x : " << x << std::endl;return x;} else std::cout << " y : " << y << std::endl; return y; } // (int)this operator int() { cout << "type int" << endl; return x;} }; // Smart overloading class overloadingPtr { overloading *ptr; public: explicit overloadingPtr(overloading* p):ptr(p){} ~overloadingPtr() { if( ptr != NULL) delete ptr; } overloading* operator->() { return ptr; } overloading& operator*() { return *ptr; } }; // 전역 오버로딩 const overloading operator*(const overloading& a, const overloading& b) { int x; int y; x = a.x*b.x; y = a.y*b.y; return overloading(x,y); } const overloading operator*(const int& a, const overloading& b) { int x; int y; x = a*b.x; y = a*b.y; return overloading(x,y); } int main_Overloading() { overloading a(12,13), b(15,16); a.Print(); b.Print(); std::cout << "--------------" << std::endl; a.operator+(b); (a+b).Print(); operator*(a,b); (a*b).Print(); a.operator+(10); (a+10).Print(); operator*(10,a); (10*a).Print(); a++; a.Print(); ++a; a.Print(); if( a==b) a.Print(); else std::cout << "a, b different" << std::endl; // operator() a(); // operator[] a[0]; a[1]; // Error // overloadingPtr p1 = new overloading(1,2); overloadingPtr p1(new overloading(1,2)); p1->Print(); (*p1).Print(); (int)a; return 0; }