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cinputalphanumeric

storing alphanumerics as an unknown number of digits in C

I'm trying to read 4 user inputs that can either be one digit, two digits, or a letter. I've tried using %c, but that can't contain any two digit numbers. I've also tried %d, but that reads all letters as 0. Is there anything that can cover all the bases?

Solution

  • Read a line and store it as a string. Then you can analyze what you got.

    Simple example:

      size_t n = 2;
  char *str;
  str = malloc (n + 1);
  getline (&str, &n, stdin);

  if (str[0]>='0'&& str[0]<='9')
    if (str[1]>='0' && str[1]<='9')
      printf("Two digits\n");
    else
      printf("One digit\n");

    Note that this is very naive, and contains almost no error detection, but it gives an idea for how to do it.