为const char * const的对比为const char *？ [英] const char * const versus const char *?

问题描述

我通过一些示例程序运行与C ++来refamiliarize我自己和我遇到了以下问题。首先，这里是例如code：

I'm running through some example programs to refamiliarize myself with C++ and I have run into the following question. First, here is the example code:

void print_string(const char * the_string)
{
    cout << the_string << endl;
}

int main () {
    print_string("What's up?");
}

在上面的code，参数为print_string本来代替了为const char * const的the_string 。这将是这更正确的？

In the above code, the parameter to print_string could have instead been const char * const the_string. Which would be more correct for this?

据我所知，所不同的是，一个是指向一个恒定字符，而一个是恒定指针为恒定的字符。但为什么这两个的工作？什么时候会是相关的？

I understand that the difference is that one is a pointer to a constant character, while one is a constant pointer to a constant character. But why do both of these work? When would it be relevant?

推荐答案

后者prevents你修改 the_string 在 print_string 。它实际上是合适的在这里，但也许是冗长推迟开发。

The latter prevents you from modifying the_string inside print_string. It would actually be appropriate here, but perhaps the verbosity put off the developer.

的char * the_string ：我可以改变字符到 the_string 点，我可以修改字符在它指向。

char* the_string : I can change the char to which the_string points, and I can modify the char at which it points.

为const char * the_string ：我可以改变字符到 the_string 点，但我不能修改字符在它指向。

const char* the_string : I can change the char to which the_string points, but I cannot modify the char at which it points.

char * const的the_string ：我不能更改字符到 the_string 点，但我可以修改字符在它指向。

char* const the_string : I cannot change the char to which the_string points, but I can modify the char at which it points.

为const char * const的the_string ：我不能更改字符到 the_string 点，我也可以修改字符在它指向。

const char* const the_string : I cannot change the char to which the_string points, nor can I modify the char at which it points.

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