title: Displaying characters in ascending order in C
body: <p>I'm just starting with C and I want to make a program that displays the alphabet in lowercase, on a single line, by
  ascending order, starting from the letter ’a’. And it should be protyped this way
  <code>void ft_print_alphabet(void);</code> 
  I'm trying this code but it's not working. </p>
  
  <pre><code>void    ft_putchar(char c);
  
  void    ft_print_alphabet(void)
  {
      char    letter;
  
      letter = 'a';
      while (letter &lt;= 'z')
      {
          ft_putchar(letter);
          letter++;
      }
  }
  
  int main(void)
  {
      ft_print_alphabet();
      return 0;
  }
  </code></pre>
  
  <p>I compile it using gcc ( Since it's what we must use ) like the following: <strong>gcc -o ftpp ftpp.c</strong>
  But I keep getting this error</p>
  
  <pre><code>Undefined symbols for architecture x86_64:
    "_ft_putchar", referenced from:
        _ft_print_alphabet in ft_print_alphabet-3d7c19.o
  ld: symbol(s) not found for architecture x86_64
  </code></pre>