int isalnum(int ch) : isalnum « ctype.h « C / ANSI-C

1. C / ANSI-C
2. ctype.h
3. isalnum

int isalnum(int ch)

    

 
//Declaration:  int isalnum(int ch); 
//Return:       returns nonzero if its argument is either a letter of the alphabet or a digit.   
                returns zero if the character is not alphanumeric.  

  
           

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

  int main(void)
  {
    char ch;

    printf(". to exit:");
    for(;;) {
      ch = getc(stdin);
      if(ch == '.')
         break;
      if(isalnum(ch))
         printf("%c is alphanumeric\n", ch);
    }

    return 0;
  }

         
/*
2 is alphanumeric
1 is alphanumeric
1
1 is alphanumeric
2
2 is alphanumeric
12
1 is alphanumeric
2 is alphanumeric
1
1 is alphanumeric
1
1 is alphanumeric
1
1 is alphanumeric
!
~
.
*/
           
       

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