我可以显式调用一个复制构造函数吗? [英] Can I call a copy constructor explicitly?
问题描述
我有点困惑的复制构造函数的机制。如果我错了,请更正我:
如果方法引用一个对象作为参数,并且类定义了一个副本construtor,那么该类使用构造函数创建一个自己的副本,并传递到函数,而不是对原始对象的引用?
此外,可以调用
Object * obj = new Object (& anotherObject);
以创建anotherObject的副本?
否,如果函数引用:
void f1(Object& o); //调用引用
,则不进行复制。如果函数取值:
void f2(Object o); //通过值调用
然后使用复制构造函数由编译器创建一个副本。 >
是的,当你说:
Object * obj = new Object anotherObject); // not& anotherObject
复制构造函数是明确使用的(假设anotherObject类型为Object)。但是,在这种情况下,使用 new
没有什么神奇之处:
Object obj2(anotherObject);
也使用复制构造函数。
I'm a little confused as to the mechanics of the copy constructor. Correct me if I'm wrong:
If a method takes a reference to an object as a parameter, and the class defines a copy construtor, then the class uses the constructor to create a copy of itself and that gets passed to the function instead of a reference to the original object?
Furthermore, one can call
Object * obj = new Object(&anotherObject);
to create a copy of anotherObject?
No, if a function take a reference:
void f1( Object & o ); // call by reference
then no copy is made. If a function takes a value:
void f2( Object o ); // call by value
then a copy is created by the compiler using the copy constructor.
And yes, when you say:
Object * obj = new Object(anotherObject); // not &anotherObject
the copy constructor is used explicitly (assuming anotherObject is of type Object.) There is nothing magic about the use of new
here, however - in this case:
Object obj2(anotherObject);
the copy constructor is also used.
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