char * arr []和char arr []有什么区别？ [英] What is the difference between the char *arr[] and char arr[] ?

问题描述

What is the difference between the

char *arr[4] = {"C","C++","Java","VBA"};

和

and

char arr[4] = {"C","C++","Java","VBA"};

推荐答案

第一个是char指针数组。所以数组的每个成员都指向一个char指针（通常是一个字符串）。

The first is an array of char pointers. So every member of the array is pointing to a char pointer (which often is a string).

char *arr[4];
arr[0]= "Codeproject";
arr[1]="is";
arr[2]="very";
arr[3]='"cool";

另一个只是一系列字符。它只存储一个字符。

你可以这样使用它：

The other is only an array of chars. It only stores ONE char.
You can use it this way:

char arr[4];
arr[0]='C';
arr[1]='o';
arr[2]='o';
arr[3]='l';

导入是要明白指针只指向内存或者对象，但不分配它。在这个示例代码中，所谓的硬编码字符串提供了内存。

Import is to understand that a pointer is ONLY pointing to memory or an object, but not allocating it. In this sample code the so called "hard coded strings" provide the memory.

尝试编译此代码，您无需询问：

< br $> b $ b

Try to compile this code and you don't need to ask:

/* is OK, a two-dimentional array of char */
char *arr[4] = {"C","C++","Java","VBA"};

< br $>

/* error C2040: 'char [4]' differs in levels of indirection from 'char *[4]' */	
char arr[4] = {"C","C++","Java","VBA"}; 

第二种情况的错误是数组是一维的，只能占用4个字符，如：

The error in the second case is that the array is one-dimentional and can take only 4 characters like:

char arr1[4] = "C";
char arr2[4] = "C++";
char arr3[4] = "Java";
char arr4[4] = "VBA"; 

根据您使用的编译器，其中一个将无法编译。

第二个版本：

Depending on the compiler you use, one of those won't compile.
The second version:

char arr[4] = {"C","C++","Java","VBA"};

声明 arr 成为四个字符的数组，然后尝试为它提供一组四个指向字符的值。

一些编译器会抱怨太多的初始化器，因为第一个指针单独提供所有数据。

第一个版本：

Declares arr to be an array of four characters, and then tries to supply it with a set of four pointer-to-character values.
Some compilers will complain "Too many initializers" because the first pointer alone provides all the data.
The first version:

char *arr[4] = {"C","C++","Java","VBA"};

声明 arr 是一个包含四个指针到字符值的数组，并为四个指针分配空间（即堆栈上可能是32位系统上的4 * 4字节，或64位系统上的8 * 4字节）。

第二个版本只分配4个字节 - 每个字符一个 - 所以你不能用字符串加载它而不会引起内存问题。

Declares arr to be an array of four pointer-to-character values, and allocates space for four pointers (i.e. probably either 4*4 bytes on a 32 bit system, or 8*4 bytes on a 64 bit system) on the stack.
The second version only ever allocates 4 bytes - one for each character - so you can't load it with "strings" without causing memory problems.

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