我需要怎么做才能使函数在C中工作 [英] What do I need to do so the function isspace work in C

问题描述

当我尝试使用cc编译C程序时，收到警告，提示我具有隐式函数声明isspace。这不是标准C库的一部分吗？我需要执行哪种导入才能使我的功能正常运行？

When I try to compile my C program with cc I get a warning that I have an implicit function declaration isspace. Isn't this part of the standard C library? Which import do I need to do so my function runs properly?

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欢呼声

推荐答案

您需要＃包括< ctype.h> 。

不过，请务必仔细阅读文档。出于历史原因，它的界面不直观。

However make sure you read the documentation carefully. Its interface is unintuitive, for historical reasons.

它设计为仅在 0 到 UCHAR_MAX （通常为255）-与 getchar（）函数返回的值相同。例如：

It's designed to work only on a value from 0 to UCHAR_MAX (usually 255) -- the same sort of value that is returned by the getchar() function. For example:

int ch = getchar();
if ( isspace(ch) )

请勿将其与 char 。如果您有一个 char 要检查空格，则必须将其转换为预期范围；例如通过强制转换为（未签名字符）：

Do not use it with a char. If you have a char that you want to check for whitespace, it must be converted to be in the expected range; e.g. by a cast to (unsigned char):

char ch = 't';
if ( isspace( (unsigned char)ch ) )

对于所有 ctype.h

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