字符串显示为奇怪的符号

发布于 2024-12-14 04:18:56 字数 459 浏览 5 评论 0原文

我在另一项作业中遇到了麻烦，其中我的字符串将 printf 作为无意义的符号，例如菱形中的问号或随机字符。

这次我试图这样做，

char *word = "blah";
printf("word: %s", word);

这给了我一些胡言乱语，甚至与单词的长度不一样。我已经包含了 string.h。

我想做的是获取一个字符串，一次将两个字母附加到字符串的前面或后面，然后从字符串的后半部分提取字符。使用以下方法附加：

int len = strlen(word);
word[len] = 'd';

另外，如何提取最后两个字符？我假设我会通过获取单词的 strlen 并将其转换为字符数组并从索引复制到索引来提取它。有更好的办法吗？另外，随机问题：什么时候使用'\0'？这种情况下需要吗？

非常感谢任何可以帮助我的人。

原文

I have been having trouble with this with another assignment where my strings would printf as nonsensical symbols, like a question mark in a diamond or random characters.

This time I am trying to do

char *word = "blah";
printf("word: %s", word);

This gives me gibberish that isn't even the same length as the word. I have included string.h.

What I am trying to do is take a string, append two letters one at a time to either the front or back of the string, and then extract the characters from the back half of the string. Using the following method to append:

int len = strlen(word);
word[len] = 'd';

Also, how do I extract say the last two characters? I'm assuming I'd extract it by getting the strlen of word and turning it into a character array and copying from indice to indice. Is there a better way? Also, random question: when do I use '\0'? Is it needed in this case?

Much thanks to anyone who can help me.

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只是偏爱你 2024-12-21 04:18:56

您的代码查找单词的长度，该数字不在末尾包含空终止符。然后，您继续使用以下行覆盖终止符：

word[len] = 'd';

因此，现在您的字符串无法正确终止，并且无法与 I/O 函数很好地配合。记住;因数从零开始。长度为 x 的字符串具有 0 到 x-1 范围内的可访问字符。

除此之外，您没有向我们展示您如何创建 word，因此那里也可能存在问题。如果您一开始就没有正确初始化它，那么您可能只是踩踏了不应该修改的内存。

编辑：好的，所以您已经发布了创建字符串的代码，这是另一个问题：

char *word = "blah";

这实际上应该是

const char *word = "blah";

因为 word 指向只读内存。您不得修改 word 指向的内容。相反，如果稍后需要修改字符串，请创建一个数组：

char word[] = "blah";

Your code finds the length of word, a number which does not include the null terminator at the end. You then proceed to overwrite the terminator with the following line:

word[len] = 'd';

So now you have a string which does not terminate properly and won't play nicely with I/O functions. Remember; indeces start at zero. A string of length x has accessible characters in the range of 0 through x-1.

Aside from that, you don't show us how you created word in the first place, so there may be a problem there as well. If you didn't initialize it properly to begin with you're probably just stomping all over memory that you shouldn't be modifying.

EDIT: Ok, so you have posted the code where you create the string, and here is another problem:

char *word = "blah";

That should really be

const char *word = "blah";

because word points to read only memory. You are not allowed to modify what word points to. Instead, create an array if you need to modify the string later on: