C ++的新手.关于常量指针的问题 [英] New to C++. Question about constant pointers

问题描述

我正在尝试通过一些网络教程来学习C ++.我没有可用的编译器，否则我会尝试一下.我不确定const指针是什么意思.这是否仅表示它始终指向相同的内存地址?你为什么要这么做?以下代码合法吗?

I am trying to learn C++ via some web tutorials. I don't have a compiler available to me, otherwise I would try this out. I'm not sure what is meant by a const pointer. Does that just mean it always points to the same memory address? Why would you ever want to do that? Would the following code be legal?

...
int * const aPointer = new int;
... //do something with aPointer
delete aPointer;
... //do something else, including possibly more 'new' statements
aPointer = new int;
...

推荐答案

记住const如何与指针一起工作的一种简单方法是记住，它始终适用于它左边的任何内容，除非它是最左边的关键字，在这种情况下，它适用于右侧.

A simple way to remember how const works with pointers is to remember that it always applies to whatever is to the left of it, unless it's the left-most keyword, in which case it applies to the right.

示例:

指向常量字符的指针: 指针可以更改为指向其他内容，但是它最初指向的char不能更改值.

Pointer to a constant char: The pointer can be changed to point to something else, but the char it initally points to cannot change value.

const char * p;

常量字符: 指针不能更改为指向其他任何东西，但是它指向的char可以更改值.

Constant pointer to a char: The pointer cannot be changed to point to anything else, but the char it points to can change value.

char *const p;

常量常量常量指针: 指针不能更改为指向其他任何东西，指针所指向的char不能更改值.

Constant pointer to a constant char: The pointer cannot be changed to point to anything else, and the char it points to cannot change value.

const char *const p;

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