Menu
×
   ❮   
HTML CSS JAVASCRIPT SQL PYTHON JAVA PHP HOW TO W3.CSS C C++ C# BOOTSTRAP REACT MYSQL JQUERY EXCEL XML DJANGO NUMPY PANDAS NODEJS R TYPESCRIPT ANGULAR GIT POSTGRESQL MONGODB ASP AI GO KOTLIN SASS VUE DSA GEN AI SCIPY AWS CYBERSECURITY DATA SCIENCE
     ❯   

C ctype isalpha() 函数

❮ C ctype 库


示例

检查字符是否为字母

char c = 'A';
if (isalpha(c)) {
  printf("%c is a letter", c);
} else {
  printf("%c is not a letter", c);
}
自己试试 »

定义和用法

如果字符是字母(a-z),则 isalpha() 函数返回一个非零值(相当于布尔值 true)。

例如,不是字母的字符: (空格)!#%&? 等。

isalpha() 函数在 <ctype.h> 头文件中定义。


语法

int isalpha(int c);

参数值

参数 描述
c 必需。字符的 ASCII 值或实际字符

技术细节

返回 一个 int 值,如果字符是字母,则该值是非零的(相当于布尔值 true)。

否则它返回 0(相当于布尔值 false)。

❮ C ctype 库

×

Contact Sales

If you want to use W3Schools services as an educational institution, team or enterprise, send us an e-mail:
[email protected]

Report Error

If you want to report an error, or if you want to make a suggestion, send us an e-mail:
[email protected]

W3Schools is optimized for learning and training. Examples might be simplified to improve reading and learning. Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness of all content. While using W3Schools, you agree to have read and accepted our terms of use, cookie and privacy policy.

Copyright 1999-2024 by Refsnes Data. All Rights Reserved. W3Schools is Powered by W3.CSS.