This is in C language. When I call rotate() in main, the function returns false for isalpha() even though the string entered for plaintext uses alphabetic characters. Perhaps it’s identifying an alphabetic character by its ASCII value (‘A’ = 65)? I tried to test that out and used (char) with the letter variable in rotate() but it didn’t change anything.

PORTION OF MAIN

string plaintext = get_string("plaintext:  ");

    int length = strlen(plaintext);
    char ciphertext[length];

    for (int i = 0; i < length; i++)
    {
        ciphertext[i] = rotate(plaintext[i], key);
    }

ROTATE FUNCTION

char rotate(char letter, int key)
{
    if (isalpha(letter) == true)
    { ...
  • @breadsmasherEnglish
    4•1 year ago

    what language? needs more context

    portion of main and function are just titles for me, if that is supposed to contain code

    • @[email protected]OP
      3•1 year ago

      Sorry. It’s in C. Updated post. Yes those are titles. I just included the relevant portions rather than the entire code.