c++构造顺序

1. 静态成员最先构造，按照静态成员初始化顺序，不是类里面的声明顺序

 

2. 父类构造

3. 非静态成员构造，按照类成员声明顺序，不是逗号初始化成员顺序。   类成员声明时就地初始化早于逗号初始化。

4. 自身构造函数

 

Demo:

class TestA
{
public:
	TestA(){
		std::cout << "TestA()" << std::endl;
	}
};


class TestB
{
public:
	TestB(int b) {
		std::cout << "TestB()" << std::endl;
	}
};

class TestC
{
public:
	TestC(int c) {
		std::cout << "TestC()" << std::endl;
	}
};

class TestD
{
public:
	TestD() {
		std::cout << "TestD()" << std::endl;
	}
};

class TestE
{
public:
	TestE() {
		std::cout << "TestE()" << std::endl;
	}
};


class Father
{
public:
	Father() {
		std::cout << "Father()" << std::endl;
	}
	~Father() {
		std::cout << "~Father()" << std::endl;
	}
};


class SonA : public Father
{
public:
	SonA(int num1, int num2)
	:m_C(num1)
	,m_B(num2)
        ,m_d(2)
	{
		std::cout << "SonA()" << std::endl;   //先Father，最后Son

                std::cout << "m_d:" << m_d << std::endl;     //m_d逗号构造晚于类成员声明时就地初始化

	}
	~SonA() {
		std::cout << "~SonA()" << std::endl;
	}
public:
	static TestD m_gD;
	static TestE m_gE;

private:
	TestA m_A;
	TestB m_B;
	TestC m_C;  //member声明顺序 A，B，C，逗号初始化顺序忽略
        int m_d = 1;
};

TestE SonA::m_gE;
TestD SonA::m_gD;   //static初始化顺序 E，D

int main()
{
	SonA son(1, 2);
}

输出：

TestE()
TestD()
Father()
TestA()
TestB()
TestC()
SonA()
m_d:2