字符串没有'\\ 0'字符？ [英] Strings without a '\0' char?

问题描述

如果错误，我定义没有'\\ 0'字符数组作为它的最后一个字符，那么什么会发生？
我问这个，因为我发现，如果我试图通过在阵列来迭代（CNT！='\\ 0'），其中CNT是作为索引到一个数组int变量，并同时打印CNT值监测发生了什么迭代的最后一个字符停止2. +额外的字符当然是随机的，但我不能得到它，为什么它停止2.Does后，编译器会自动插入一个'\\ 0'字符？链接到相关的文件将AP preciated。

If by mistake,I define a char array with no '\0' as its last character,what happens then? I'm asking this because I noticed that if I try to iterate through the array while(cnt!='\0'),where cnt is a int variable used as an index to the array,and simultaneously print the cnt values to monitor what's happening the iteration stops at the last character +2.The extra characters are of course random but I can't get it why it has to stop after 2.Does the compiler automatically inserts a '\0' character?Links to relevant documentation would be appreciated.

要弄清楚我举一个example.Let的说，数组STR包含单词DOH（没有'\\ 0'）。在每个循环打印CNT变量会给我这个
卫生署+
或卫生署^
等

To make it clear I give an example.Let's say that the array "str" contains the word doh(with no '\0').Printing the cnt variable at every loop would give me this doh+ or doh^ and so on.

推荐答案

修改（未定义行为）

访问数组边界之外的数组元素是不确定的行为。结果
调用字符串函数比C字符串的任何其他未定义行为。结果
不这样做！

Accessing array elements outside of the array boundaries is undefined behaviour.
Calling string functions with anything other than a C string is undefined behaviour.
Don't do it!

的 C字符串是，并包括 '\\ 0'（NUL终止）终止字节序列。所有字节必须属于同一对象的

A C string is a sequence of bytes terminated by and including a '\0' (NUL terminator). All the bytes must belong to the same object.

总之，你看到的是一个巧合！

Anyway, what you see is a coincidence!

但它也可能发生这样的

                        ,------------------ garbage
                        | ,---------------- str[cnt] (when cnt == 4, no bounds-checking)
memory ----> [...|d|o|h|*|0|0|0|4|...]
                  |   |   \_____/  -------- cnt (big-endian, properly 4-byte aligned)
                  \___/  ------------------ str

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