这是因为,constructor initializer list是直接初始化了数据成员(1步),而如果赋值在constructor body里,就是在进入body前进行了初始化,然后在body中进行赋值(2步),这会涉及到效率问题。 除了效率问题,还有一些情况,我们不得不、必须使用constructor initializer list。在看下去之前,不妨想一想,在什么情况下,只能用...
本文探讨构造函数初始值列表(constructor initializer list)这一C++特性，主要关注其行为、适用场景以及相关细节。构造函数初始值列表用于在构造函数定义时直接初始化数据成员，简化代码并提升效率。构造函数初始值列表的行为遵循三步初始化流程。首先，使用初始值列表中的值进行初始化（通过调用与实参相对应的构造...
参数是被类型的const &, 然后在constructor initializer list里对一个一个成员变量进行拷贝。 下面我们来具体讲一下合成的拷贝构造函数的行为: (1) 逐个成员拷贝; 数组逐个元素拷贝; Generally, the synthesized copy constructor memberwise copies the members of its argument into the object being created. The co...
With C++ classes one can have the option of initializing the class's data members in the constructor's initializer list. Using constructor initializer lists in C++ Builder is discussed. It is shown that they represent the preferred way of initializing a class.Kent Reisdorph...
In the following example, our Foo(int, int) constructor has been updated to use a member initializer list to initialize m_x, and m_y: #include <iostream> class Foo { private: int m_x {}; int m_y {}; public: Foo(int x, int y) : m_x { x }, m_y { y } // here's ...
Hi I thought classname obj{Val} is initializer list... So, what is classname obj = {Val} Does second option i.e. with equal to call implicit constructor ? #include <iostream> using namespace std; class X { public: int x; explicit X(int x) : x(x){} }; int main() { X a ...
structS{intn;S(int);// constructor declarationS():n(7){}// constructor definition:// ": n(7)" is the initializer list// ": n(7) {}" is the function body};S::S(intx):n{x}{}// constructor definition: ": n{x}" is the initializer listintmain(){S s;// calls S::S()S...
Test(int t):t(t) {} //Initializer list must be used int getT() { return t; } }; int main() { Test t1(10); cout<<t1.getT(); return 0; } /* OUTPUT: 10 */ The above code is just an example for syntax of Initializer list. In the above code, x and y ...
{ "some_name", "some_address" }; StorageBox sb1(1, 2, 3, label1); // passing a temporary label StorageBox sb2(3, 4, 5, Label{ "another name", "another address" }); // passing a temporary label as an initializer list StorageBox sb3(1, 2, 3, {"myname", "myaddress"});...
详细了解 Microsoft.CodeAnalysis.CSharp.Syntax 命名空间中的 Microsoft.CodeAnalysis.CSharp.Syntax.ConstructorInitializerSyntax.ArgumentList。