C++双目运算符+=的重载详解

class Complex
{
public:
	Complex(int a, int b)
		: _a(a)
		, _b(b)
	{}
	Complex& operator+= (Complex& other)
	{
		this->_a += other._a;
		this->_b += other._b;
		return *this;
	}
	void print()
	{
		cout << _a << endl;
		cout << _b << endl;
	}
private:
	int _a;
	int _b;
};
void TestLei()
{
	int a = 10, b = 20, c = 30;
	Complex c1(10, 20);
	Complex c2(20, 30);
	Complex c3(30, 40);
	c1 += c2 += c3;
	c1.print();
}

class Complex
{
public:
	Complex(int a, int b)
		: _a(a)
		, _b(b)
	{}
	friend Complex& operator+= (Complex& c1, Complex& c2)
	{
		c1._a += c2._a;
		c1._b += c2._b;
		return c1;
	}
	void print()
	{
		cout << _a << endl;
		cout << _b << endl;
	}
private:
	int _a;
	int _b;
};
void TestFriend()
{
	int a = 10, b = 20, c = 30;
	Complex c1(10, 20);
	Complex c2(20, 30);
	Complex c3(30, 40);
	c1 += c2 += c3;
	c1.print();
}

b ? x : y

class Test
{
public:
	Test(int t = 0)
		:_t(t)
	{}
	Test& operator++() // 前置++
	{
		++_t;
		return *this;
	}
	Test operator++(int)// 后置++
	{
		Test temp = *this; 
		++_t;
		return temp;
	}
	Test& operator--()// 前置--
	{
		--_t;
		return *this;
	}
	Test operator--(int)// 后置--
	{
		Test temp = *this;
		--_t;
		return temp;
	}
	int Result()
	{
		return _t;
	}
private:
	int _t;
};