C++中多个参数的初始化顺序问题

C++中多个参数的初始化顺序问题

决定参数初始化顺序的因素

1.跟参数列表的初始化顺序无关
2.取决于声明对象的顺序

实例

#define _CRT_SECURE_NO_WARNINGS 1
#include
#include
using namespace std;


class A
{
public:
	A(int x) :m_x(x)
	{
		cout << "A::A(int)" << endl;
	}
private:
	int m_x;
};
class B
{
public:
	B(int y) :m_y(y)
	{
		cout << "B::B(int)" << endl;
	}
private:
	int m_y;
};
class C
{
public:
	C(int z) :m_z(z)
	{
		cout << "C::C(int)" << endl;
	}
private:
	int m_z;
};

class Test
{
public:
	Test(int a, int b, int c) :m_a(a), m_b(b), m_c(c)
	{}
private:
	A m_a;
	B m_b;
	C m_c;

};
int main()
{
	Test t(10, 20, 30);
}

更改参数列表初始化顺序

class Test
{
public:
	Test(int a, int b, int c) : m_c(c) ,m_b(b),m_a(a)
	{}
private:
	A m_a;
	B m_b;
	C m_c;

};
int main()
{
	Test t(10, 20, 30);
	system("pause");
}

更改声明顺序

class Test
{
public:
	Test(int a, int b, int c) :m_a(a), m_b(b), m_c(c)
	{}
private:
	B m_b;
	C m_c;
    A m_a;
};
int main()
{
	Test t(10, 20, 30);
	system("pause");
}