isalnum

isalnum

测试字符是否为英文(alpha character)或数字(numeric character)

相关函数

isalpha，isdigit，islower，isupper

表头文件

[code]#include <ctype.h>

定义函数

[code]int isalnum(int c)

函数说明

检查参数c是否为英文字母或阿拉伯数字，在标准c中相当于使用“isalpha(c) || isdigit(c)”做测试。

返回值

若参数c为字母或数字，则返回TRUE，否则返回NULL(0)。

附加说明

此为宏定义，非真正函数。

范例

[code]/* 找出str 字符串中为英文字母或数字的字符*/

#include <ctype.h>
#include <stdio.h>

int main()
{
char str[] = "123c@#FDsP[e?";
for(int i = 0; str[i] != 0; i++)
if(isalnum(str[i]))
printf("%c is an alphanumeric character\n",str[i]);
return 0;

}

执行

[code]1 is an alphanumeric character
2 is an alphanumeric character
3 is an alphanumeric character
c is an alphanumeric character
F is an alphanumeric character
D is an alphanumeric character
s is an alphanumeric character
P is an alphanumeric character
e is an alphanumeric character

• 点赞
• 收藏
• 分享
• 文章举报