合法的C标示符(判断是否是数字或字母)

 1 #include<stdio.h>

 2 #include<ctype.h>

 3 #include<string.h>

 4 const int MAXN = 1010 ;

 5 int main()

 6 {

 7     int n ;

 8     scanf("%d%*c",&n) ;

 9     getchar() ;

10     char ch[MAXN] ;

11     for(int i = 1 ; i <= n ; i++)

12     {

13         gets(ch) ;

14         int flag = 1 ;

15         int len = strlen(ch) ;

16         if(ch[0] == '_'||isalpha(ch[0]))

17         {

18             for(int i = 1 ; i <= len-1 ; i++)

19             {

20                 if((!isalpha(ch[i]))&&(!isdigit(ch[i]))&&(ch[i] != '_'))

21                 {

22                     flag = 0 ;

23                     break ;

24                 }

25             }

26             if(flag)

27                 printf("Yes\n");

28             else printf("No\n") ;

29         }

30         else

31             printf("No\n") ;

32     }

33     return 0 ;

34 }

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