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- Is there a difference between copy initialization and direct initialization? 8 answers
- 复制初始化和直接初始化之间有区别吗? 8个答案
There are two type of object initialisation using copy constructor:
使用复制构造函数有两种类型的对象初始化:
Class object2(val1, val2); // <--- (1)
Same can be done by copying the contents of another class:
同样可以通过复制另一个类的内容来完成:
Class object1(val1, val2);
Class object2 = object1; // <--- (2)
What is the difference between (1) and (2) ? Are they explicit calls and implicit calls or does it have to do with operator overloading?
(1)和(2)之间有什么区别?它们是显式调用和隐式调用还是与运算符重载有关?
2 个解决方案
#1
2
Both constructs use constructors, but different constructors. First is a constructor taking two arguments, second is normally the copy constructor (can be defaulted). The explicit declarations should be like:
两个构造都使用构造函数,但使用不同的构造函数。首先是一个带有两个参数的构造函数,第二个通常是复制构造函数(可以是默认的)。显式声明应该是:
class Class {
// constructor taking 2 args
Class(int val1, const std::string& val2);
// copy ctor
Class(const Class& other);
/* you could optionaly have a move ctor:
Class(Class&& other); */
...
};
#2
1
Here
这里
1. case 1
Class object2(val1, val2);
will call the constructor with two arguments
将使用两个参数调用构造函数
Class(type a, type b);
2. case 2
Class object2 = object1;
will call the copy constructor
将调用复制构造函数
Class(const Class&);
演示
#1
2
Both constructs use constructors, but different constructors. First is a constructor taking two arguments, second is normally the copy constructor (can be defaulted). The explicit declarations should be like:
两个构造都使用构造函数,但使用不同的构造函数。首先是一个带有两个参数的构造函数,第二个通常是复制构造函数(可以是默认的)。显式声明应该是:
class Class {
// constructor taking 2 args
Class(int val1, const std::string& val2);
// copy ctor
Class(const Class& other);
/* you could optionaly have a move ctor:
Class(Class&& other); */
...
};
#2
1
Here
这里
1. case 1
Class object2(val1, val2);
will call the constructor with two arguments
将使用两个参数调用构造函数
Class(type a, type b);
2. case 2
Class object2 = object1;
will call the copy constructor
将调用复制构造函数
Class(const Class&);
演示