C语言 为什么在字符串数组中添加空字符？
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Why adding a Null Character in a String array?
提问by Anurag-Sharma
I know that we have to use a null character to terminate a string array like this:
我知道我们必须使用空字符来终止这样的字符串数组：
char str[5] = { 'A','N','S','char str1[5]="ANS";
' };
But I just wanted to know why is it essential to use a null character to terminate an array like this?
但我只是想知道为什么必须使用空字符来终止这样的数组？
Also why don't we add a null charater to terminate these :-
另外，我们为什么不添加一个空字符来终止这些：-
char source[]="Test"; // Actually: T e s t ##代码## ('##代码##' is the NULL-character)
char dest[8];
int i=0;
char curr;
do {
curr = source[i];
dest[i] = curr;
i++;
} while(curr); //Will loop as long as condition is TRUE, ie. non-zero, all chars but NULL.
回答by Baard Kopperud
The NULL-termination is what differentiates a char array from a string (a NULL-terminated char-array) in C. Most string-manipulating functions relies on NULL to know when the string is finished (and its job is done), and won't work with simple char-array (eg. they'll keep on working past the boundaries of the array, and continue until it finds a NULL somewhere in memory - often corrupting memory as it goes).
NULL 终止是 C 中字符数组与字符串（以 NULL 结尾的字符数组）的区别。大多数字符串操作函数依赖于 NULL 来知道字符串何时完成（以及它的工作已完成），并赢得不能使用简单的字符数组（例如，它们将继续工作超过数组的边界，并继续直到它在内存中的某处找到 NULL - 通常会在运行时破坏内存）。
In C, 0 (the integer value) is considered boolean FALSE - all other values are considered TRUE. if, forand whileuses 0 (FALSE) or non-zero (TRUE) to determent how to branch or if to loop. char is an integer type, an the NULL-character (\0) is actually and simply a char with the decimal integer value 0 - ie. FALSE. This make it very simple to make functions for things like manipulating or copying strings, as they can safely loop as long as the character it's working on is non-zero (ie. TRUE) and stop when it encounters the NULL-character (ie. FALSE) - as this signifies the end of the string. It makes very simple loops, since we don't have to compare, we just need to know if it's 0 (FALSE) or not (TRUE).
在 C 中，0（整数值）被认为是布尔值 FALSE - 所有其他值都被认为是 TRUE。 if、for和while使用 0 (FALSE) 或非零 (TRUE) 来决定如何分支或是否循环。char 是整数类型，NULL 字符 (\0) 实际上只是一个具有十进制整数值 0 的字符 - 即。错误的。这使得为诸如操作或复制字符串之类的事情制作函数变得非常简单，因为只要它正在处理的字符非零（即 TRUE），它们就可以安全地循环，并在遇到 NULL 字符时停止（即FALSE) - 因为这表示字符串的结尾。它进行了非常简单的循环，因为我们不必进行比较，我们只需要知道它是 0 (FALSE) 还是不是 (TRUE)。
Example:
例子：
##代码##回答by Tom Studee
It isnt essentialbut if you are using any of the standard libraries, they all expect it.
这不是必需的，但如果您使用任何标准库，他们都期望它。
