我是否正确初始化了我的C ++参考变量? [英] Am I initializing my C++ reference variables correctly?

问题描述

我已尝试通过Google搜索此问题，但找不到与我相关的任何内容.所以我一定在寻找错误的东西；尽管如此，我还是很乐意的...

I've tried to Google this issue, and I can't find anything that I see as relevant. So I must be looking for the wrong thing; none the less, I'd appreciate some advice...

Foobar &foobar = *new Foobar(someArg, anotherArg);

是我还是看起来很臭?

我了解new关键字是专为与指针一起使用而设计的:

I understand that the new keyword is designed for use with pointers (as such):

Foobar *foobar = new Foobar(someArg, anotherArg);

但是，如果您不需要该实例上的指针，而想使用引用，该怎么办?或者，是不需要显式初始化它的情况(很像局部变量)?如果是这种情况，我要用参数初始化怎么办?

But what if you don't require a pointer on that instance, and you would like to use a reference instead? Or, is it the case that you don't need to explicitly initialize it (much like local variables); and if this is the case, what if I want to initialize with parameters?

以下内容不起作用(除非我做错了):

The following does not work (unless I'm doing something wrong):

// the last argument is of type: int
Foobar &foobar(someArg, anotherArg);

...给出编译器错误:

... gives the compiler error:

初始化器表达式列表被视为复合表达式 类型为"Foobar&"的非常量引用的无效初始化 来自"int"类型的临时

initializer expression list treated as compound expression invalid initialization of non-const reference of type ‘Foobar&’ from a temporary of type ‘int’

这似乎也不起作用:

Foobar &foobar = Foobar(someArg, anotherArg);

...给出编译器错误:

... gives the compiler error:

错误:类型的非常量引用的无效初始化 类型为"Foobar"的临时广告中的"Foobar&"

error: invalid initialization of non-const reference of type ‘Foobar&’ from a temporary of type ‘Foobar’

更新1:

请记住，我要返回此值，所以我不想使用局部变量；我想在堆而不是堆栈上使用一个值:

Update 1:

Bare in mind that I am returning this value, so I don't want to use a local variable; I want to use a value on the heap, not the stack:

Foobar &helloWorld()
{
    Foobar &foobar = *new Foobar(someArg, anotherArg);
    foobar.HelloWorld();
    return foobar;
}

我应该只使用指针，还是完全有效?

Should I just be using pointers instead, or is this completely valid?

推荐答案

为什么您认为根本需要使用new和reference?为什么不呢?

Why do you think you need to use new and references at all? Why not:

Foobar foobar(someArg, anotherArg);

对于您的函数-返回一个值:

For your function - return a value:

Foobar helloWorld()
{
    Foobar foobar(someArg, anotherArg);
    foobar.HelloWorld();
    return foobar;
}

或指针:

Foobar * helloWorld()
{
    Foobar * foobar = new Foobar(someArg, anotherArg);
    foobar->HelloWorld();
    return foobar;
}

如果执行此操作，则调用方有责任在某个时候删除分配的对象.

If you do this - the caller is responsible for deleting the allocated object at some point.

从非成员函数返回的地方通常不会明智地使用引用，因为您想引用的东西通常不再存在.

Return from a non-member function is one place where references can typically not be used sensibly, as the thing you would like to refer to usually no longer exists.

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