指针/在C / C数组语法（字符** P，* P [N]）+ [英] Pointer / Array syntax (char **p, *p[n]) in C/C++

问题描述

有关指针，我越来越混淆声明和函数参数上如果一个函数需要一个（*数组[n]）参数时使用的char **或字符*或*阵列[N]等一样，我将它传递一个**类型？

For pointers, I'm getting confused with declarations and function parameters on when to use char ** or char * or *array[n], etc. Like if a function takes a (*array[n]) parameter, do I pass it a **type?

我尝试使用左右规则，知道是p是一个指针的指针为char（字符** P），p是n个指针数组（* P [N]），但有人说，* p [n]和** p为基本上相等。是真的吗？

I try using the Right-Left rule and know that p would be a pointer to a pointer to a char (char **p), and p is an array of n pointers (*p[n]), but someone said that *p[n] and **p are essentially equivalent. Is that true?

推荐答案

阅读Ç声明符（这是与*和[]变量的一部分）是相当细致入微。有一些网站与技巧：

Reading C declarators (that's the part of the variable with the * and []) is fairly nuanced. There are some websites with tips:

• http://www.antlr.org/wiki/display/CS652/How+To+Read+C+Declarations


• http://www.ericgiguere.com/articles/reading-c-declarations.html

A 的char ** 是一个指针（可能是多个）指针（S）到（可能是多个）字符（S）。例如，它可能是一个指向一个字符串的指针，或指向串的指针数组。

A char** is a pointer to (possible multiple) pointer(s) to (possibly multiple) char(s). For example, it might be a pointer to a string pointer, or a pointer to an array of string pointers.

A 的char * [] 是指向字符数组。当你有一个函数，这个作为一个参数，C编译器使得它腐烂变成了的char ** 。这只是发生在第一层...所以，采取了复杂的例子，的char * [4] [] 变成的char *（*） 4] 。阅读上面这样你就可以明白这意味着什么赫克的链接。

A char*[] is an array of pointers to char. When you have a function that takes this as a parameter, the C compiler makes it "decay" into a char**. This only happens to the first layer... so, taking a complicated example, char*[4][] becomes char*(*)[4]. Read the links above so you can understand what the heck that means.

或者你也可以做一个（非常明智）的事情，让一堆类型定义的。我不这样做，但直到你擅长阅读说明符，这是一个好主意。

Or you can do a (very sensible) thing and make a bunch of typedefs. I don't do this, but until you're good at reading declarators, it's a good idea.

typedef char * stringp;
void func(stringp array[]) { ... }
static stringp FOUR_STRINGS[4] = { ... };

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