feedback for a java program

feedback.md

Awesome use of control characters to clear the terminal and reset the cursor postion. I was never doing that stuff in these classes. My programs always just printed out stuff over and over and over. So, pro stuff right there!

Overall Structure

Bring the main method up so it is the first method to appear in the file.

Make more methods to encapsulate different parts of the main method. Think of the main method more as a table of contents than paragraphs of code explaining the program.

I'd aim for something like this:

public static void main(String[] args) throws InterruptedException {
  welcomeMessage();

  int choice = promptForSize();
  ponderChoice(choice);

  printColumnCombos();
  printGame();

  printResults(moves);
} 

Java Styles

• Global variables (str, moveWords, col1, col2, col3, moves) should be in ALL_UPPERCASE (also, you could probably localize their scope in the main method and pass them as parameters, but whatever.)
• Prefer ArrayList<String> over ArrayList< String > (no spaces).
• Prefer fromRod over from_rod (camelCase, not snake_case).

There's a weird thing I wonder if they've talked about in class that's "interface vs implementation." You should use interfaces to declare the type of things and use implementations to actually create things.

Basically, prefer List over ArrayList or LinkedList on the left where you declare the type. The reason for this is the two implementations ArrayList and LinkedList are both implementations of the List interface. If you declare them as the more general List you can use them in more places. It is definitely a "rectangle vs square" situation.

private static List<Integer> col3 = new ArrayList<Integer>();
private static List<Integer> col4 = new LinkedList<Integer>();

Being able to use them in more places might make more sense if we're talking about declaring the types of parameters for a method. If you declare the parameter as having type List you can pass in either ArrayList or LinkedList. If you delcare a method as just ArrayList you couldn't pass in a LinkedList.

// This declaration is more broad
private static someMethod(List<Integer> list) {}

// This type declaration is more restrictive
private static someMethod(ArrayList<Integer> list) {}

Never abbreviate words. You write ind instead of index in a few places. Abbreviations don't really saving anything. They tend to contribute to confusion and inconsistency. (OK I'm also a hypocrite here because I think "col" for "column" is alright.)

Here's a personal preference from me. Prefer longer variable names. Instead of n = scan.nextInt() consider choice = scan.nextInt(). Longer variable names are easier to search for when you're trying to find where else they occur in code.

Single variable names I personally find especially hard to search for. When I write any programs with x and y coordinates and weird tick I've developed is always writing them as xx and yy so I can search for them easier and the letters "x" and "y" in other variable names don't barge in my search results.

Utility Methods

Make more utility methods!

Screen Refresh Cursor Reset Method

You have these lines of code repeating several times. Make a method called something like refresh or something even cooler like cursorBlit() so you can call that method instead of writing this code redundantly everywhere.

System.out.print("\033[2J"); // clear terminal
System.out.print("\033[0;0H"); // place cursor at top left corner

Message Print Method

Similarly you can reduce redundancy in the structure of printing these messages. Make a method called display(String message) or something.

printGame(n); // print first state of the game before computation
System.out.println();
System.out.println("Hmm, let me think here.");

// ... other code ...

printGame(n); // rerprint first state of the game
System.out.println();
System.out.println("Ohh, I know! here look:");

private static void display(String message) {
  printGame(n);
  System.out.println();
  System.out.println(message);
}

Character Repeat Method

You have a lot of for loops that exist just to print out a character a certain amount of times. Prime canidate to make a method for that.

private static void repeatChar(String text, int times) {
  for (int i = 0; i < times; i++) {
    System.out.print(" ");
  }
}

int ind = col1.get(i);
for (int y = 0; y < n - ind; y++) {
  System.out.print(" ");
}

for (int y = 0; y < ind; y++) {
  System.out.print("-");
}
System.out.print(ind);

if (ind > 9) {
  for (int y = 0; y < ind - 1; y++) {
    System.out.print("-");
  }
} else {
  for (int y = 0; y < ind; y++) {
    System.out.print("-");
  }
}
for (int y = 0; y < n - ind; y++) {
  System.out.print(" ");
}

int ind = col1.get(i);
repeatChar(" ", n - ind);
repeatChar("-", ind);

System.out.print(ind);

if (ind > 9) {
  repeatChar("-", ind - 1);
} else {
  repeatChar("-", ind);
}

repeatChar(" ", n - ind);

Column Combo Method

You repeat this structure of code several times. You can parameterize it.

// ...
} else if (str.get(i).charAt(1) == 'A' && str.get(i).charAt(2) == 'C') {
  int disc = col1.get(col1.size() - 1);
  int index = col1.size() - 1;
  col1.remove(index);
  col3.add(disc);
} else if (str.get(i).charAt(1) == 'B' && str.get(i).charAt(2) == 'C') {
  int disc = col2.get(col2.size() - 1);
  int index = col2.size() - 1;
  col2.remove(index);
  col3.add(disc);
// ...

columnCombo('A', 'C', col1, col3);
columnCombo('B', 'C', col2, col3);
// ...


private static columnCombo(Character char1, Character char2,
    List<Integer> addColumn, List<Integer> removeColumn) {
  if (str.get(i).charAt(1) == char1 && str.get(i).charAt(2) == char2) {
    int disc = removeColumn.get(removeColumn.size() - 1);
    int index = removeColumn.size() - 1;
    removeColumn.remove(index);
    addColumn.add(disc);
  }
}