Verifying single digit input

I was waondering if anyone could tell me how to verify a single digit input. I've been able to catch an Alpha and also a number greater than nine and less than zero but just can't seem to put the two together. This is a school assignment and we've been told that verification is not necessary but this has really been bugging me. :confused:

Verify what? Why can't you use isdigit?

Or even better, isalnum. :)

Quzah.

I thought he wanted to check whether the input was a digit or not. :p

Did you read my PM by the way? :)

Thanks for the quik reply. I'm afraid your dealing with a complete n00b here. I tried that but was probably running into 'type' problems. If I understand it right this requites a char argument, right. and returns a 1 if true

I think a light has come on. If I use isdigit and also want catch a double digit I need to use a sting and test the second character as well. Am I getting close? :confused:

Thanks for your help and letting me ramble. I think I got it. This seems to work :D

Code:

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#include <stdio.h>

int main()
{
  char num[10];
  int test = 0;
 
  printf ("Enter a single digit:> ");
  scanf("%s", &num);
  while (test == 0) {
    if (isdigit(num[0])&&(num[1]==NULL)) {
        printf("The number you entered was %c.\n", num[0]);
        test = 1;     
        }
    else {
      printf("Not a single digit\nTry again:> ");
      scanf("%s", &num);
      }
  }
  system("PAUSE");       
  return(0);
}

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This is wrong in a scary way:

Code:

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num[1]==NULL

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NULL should only be used when dealing with pointers. It's confusing because you hear strings are "null-terminated". Well, in that case it's talking about the ASCII value 0, not the NULL macro definition, which is generally defined as (void *)0. Any of these alternatives would be a whole lot better:

Code:

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!num[1]
num[1]==0
num[1]=='\0'

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Thankyou :o