int isalpha（int c）

描述 (Description)

C库函数void isalpha(int c)检查传递的字符是否是字母。

声明 (Declaration)

以下是isalpha（）函数的声明。

int isalpha(int c);

参数 (Parameters)

• c - 这是要检查的字符。

返回值 (Return Value)

如果c是字母表，则此函数返回非零值，否则返回0。

例子 (Example)

以下示例显示了isalpha（）函数的用法。

#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);
}

让我们编译并运行上面的程序，产生以下结果 -

var1 = |d| is an alphabet                                                   
var2 = |2| is not an alphabet                                               
var3 = |        | is not an alphabet                                        
var4 = | | is not an alphabet