＜ctype.h＞ - isalpha()

小咪咪 2022-10-13 15:59 72阅读 0赞

**作用：**  
检查所传的字符是否是字母

**声明：**

int isalpha(int c);

**参数：**  
要检测的字符。它可以是一个有效的字符（被转换为 int 类型），也可以是 EOF（表示无效的字符）

**返回值：**  
返回值为非零（真）表示c是字母，返回值为零（假）表示c不是字母。

**实例：**

#include <stdio.h>
    #include <ctype.h>
    
    int main () {
       int var1 = 'd';
       int var2 = '2';
       int var3 = '\t';
       int var4 = ' ';
        
       if( isalpha(var1) ) {
          printf("var1 = |%c| is an alphabet\n", var1 );
       } else {
          printf("var1 = |%c| is not an alphabet\n", var1 );
       }
       
       if( isalpha(var2) ) {
          printf("var2 = |%c| is an alphabet\n", var2 );
       } else {
          printf("var2 = |%c| is not an alphabet\n", var2 );
       }
       
       if( isalpha(var3) ) {
          printf("var3 = |%c| is an alphabet\n", var3 );
       } else {
          printf("var3 = |%c| is not an alphabet\n", var3 );
       }
       
       if( isalpha(var4) ) {
          printf("var4 = |%c| is an alphabet\n", var4 );
       } else {
          printf("var4 = |%c| is not an alphabet\n", var4 );
       }
       
       return(0);
    }

输出：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N1cGVyODI4_size_16_color_FFFFFF_t_70][]

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