构造函数链接在C ++中

问题描述

我对构造函数链接的理解是，当一个类中有多个构造函数（重载构造函数）时，如果其中一个试图调用另一个构造函数，那么
这个过程称为CON​​STRUCTOR CHAINING，不支持在C ++中。
最近我在阅读在线材料的过程中遇到了这个段落....它像这样...

My understanding of constructor chaining is that , when there are more than one constructors in a class (overloaded constructors) , if one of them tries to call another constructor,thenthis process is called CONSTRUCTOR CHAINING , which is not supported in C++ .Recently I came across this paragraph while reading online material.... It goes like this ...

调用构造函数的成员函数是否也来自构造函数链接？

Does a member function calling the constructor also come under constructor chaining ??Please throw some light on this topic in C++ .

推荐答案

该段落基本上说：

class X
{
   void Init(params) {/*common initing code here*/ }
   X(params1) { Init(someParams); /*custom code*/ }
   X(params2) { Init(someOtherParams); /*custom code*/ }
};

您不能从成员函数调用构造函数。你似乎已经做到了，但这是一个错觉：

You cannot call a constructor from a member function either. It may seem to you that you've done it, but that's an illusion:

class X
{
public:
    X(int i):i(i){}
    void f()
    {
       X(3); //this just creates a temprorary - doesn't call the ctor on this instance
    }
    int i;
};

int main()
{
    using std::cout;
    X x(4);
    cout << x.i << "\n"; //prints 4
    x.f();
    cout << x.i << "\n"; //prints 4 again
}

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