如何使用C从键盘读取字符串? [英] How to read string from keyboard using C?

问题描述

我想读取用户输入的字符串.我不知道字符串的长度.由于C中没有字符串，所以我声明了一个指针:

I want to read a string entered by the user. I don't know the length of the string. As there are no strings in C I declared a pointer:

char * word;

并使用 scanf 从键盘读取输入:

and used scanf to read input from the keyboard:

scanf("%s" , word) ;

但是我遇到了细分错误.

but I got a segmentation fault.

当长度未知时，如何在C中从键盘读取输入?

How can I read input from the keyboard in C when the length is unknown ?

推荐答案

您没有为 word 分配存储空间-它只是一个

You have no storage allocated for word - it's just a dangling pointer.

更改:

char * word;

收件人:

char word[256];

请注意，这里的256是一个任意选择-该缓冲区的大小必须大于您可能遇到的最大字符串.

Note that 256 is an arbitrary choice here - the size of this buffer needs to be greater than the largest possible string that you might encounter.

还请注意，与 scanf 用于读取任意长度的字符串，因为它采用了 size 参数，该参数反过来有助于防止缓冲区溢出:

Note also that fgets is a better (safer) option then scanf for reading arbitrary length strings, in that it takes a size argument, which in turn helps to prevent buffer overflows:

 fgets(word, sizeof(word), stdin);

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