title: Python Nested loops: printed seats
body: <p>Given rows and cols, print a list of all seats in a theater. Rows are numbered, columns lettered, as in 1A or 3E. Print a space after each seat, including after the last. 
  Ex: <code>num_rows = 2</code> and <code>num_cols = 3</code> prints:
  1A 1B 1C 2A 2B 2C</p>
  
  <pre><code>num_rows = 2
  num_cols = 3
  c1 = 1
  while c1 &lt;= num_rows:
      c2 = 'A'
      while c2 &lt;= 'C':
          print('%s%s' % (c1, c2), end=' ')
          c2 = chr(ord(c2) + 1)
      c1 += 1
  print()
  </code></pre>
  
  <p>Output returns correctly when I test with 2 rows and 3 columns or with 5 rows and 3 columns. However, when I test with 0 columns, it returns "1A 1B 1C 2A 2B 2C 3A 3B 3C 4A 4B 4C 5A 5B 5C" when it should return nothing. I tried changing c2 = 'A' into c2 = num_cols, but didn't change anything.</p>