courseID validation.txt

 int x = courseId.length();
    boolean flag = true;
    if (x == 5)
    {
      
      for (int i = 0; i < 2; i++)
      {
        if (!(courseId.charAt(i) >= 'A' && courseId.charAt(i) <= 'Z'))
        {
          flag = false;
          break;
        }
      }
      
      for (int i = 2; i < 5 && flag; i++)
      {
        if (!(courseId.charAt(i) >= '0' && courseId.charAt(i) <= '9'))
        {
          flag = false;
          break;
        }
      }
    }
    else if( x == 6)
    {
      if( courseId.charAt(5) == 'L')
      {
        for (int i = 0; i < 2; i++)
        {
          if (!(courseId.charAt(i) >= 'A' && courseId.charAt(i) <= 'Z'))
          {
            flag = false;
            break;
          }
        }
        
        for (int i = 2; i < 5 && flag; i++)
        {
          if (!(courseId.charAt(i) >= '0' && courseId.charAt(i) <= '9'))
          {
            flag = false;
            break;
          }
        }
      }
      
    }
    
    return flag;