指向对象的C ++指针 [英] C++ pointer to objects

问题描述

在C ++中，是否总是使用new关键字初始化指向对象的指针?

In C++ do you always have initialize a pointer to an object with the new keyword?

或者您也可以拥有它:

MyClass *myclass;

myclass->DoSomething();

我认为这是分配给堆栈而不是堆的指针，但是由于对象通常是堆分配的，所以我认为我的理论可能是错误的??

I thought this was a pointer allocated on the stack instead of the heap, but since objects are normally heap allocated, I think my theory is probably faulty??

请咨询.

推荐答案

不，您可以使用指针来堆栈分配的对象:

No, you can have pointers to stack allocated objects:

MyClass *myclass;
MyClass c;
myclass = & c;
myclass->DoSomething();

当使用指针作为函数参数时，这当然很常见:

This is of course common when using pointers as function parameters:

void f( MyClass * p ) {
    p->DoSomething();
}

int main() {
    MyClass c;
    f( & c );
}

尽管如此，还是必须始终初始化指针.您的代码:

One way or another though, the pointer must always be initialised. Your code:

MyClass *myclass;
myclass->DoSomething();

导致这种可怕的状况，不确定的行为.

leads to that dreaded condition, undefined behaviour.

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