Can you instantiate a variable within method parentheses?

Question

Looking at the exercise here, the first place we see the 'char tile' variable mentioned is inside the parameters of the 'addTile' method. Does the variable not need to be instantiated somewhere in the class first before it can be passed into the method?

(Please correct any inaccurately used terminology in my question!)

Many thanks.

ScrabblePlayer.java

public class ScrabblePlayer {
  // A String representing all of the tiles that this player has
  private String tiles;

  public ScrabblePlayer() {
    tiles = "";
  }

  public String getTiles() {
    return tiles;
  }

  public void addTile(char tile) {
    // TODO: Add the tile to tiles

  }

  public boolean hasTile(char tile) {
    // TODO: Determine if user has the tile passed in
    return false;
  }

}

Answer 1 · 2017-02-01T21:31:51Z

February 1, 2017 9:31pm

No it does not have to exist to be used as a parameter name. In the parameter list of a method you state what type of argument you accept and what variable name you want that argument to have within your method. So by defining tile in the parameter list you tell Java to take the first argument passed in and create a variable called tile within your method that contains the contents of that argument.

You don't see the code that actually calls this method, but let's say it looks like this:

addTile('a');

With that code the tile parameter would be set equal to a within your method. The argument to parameter binding happens entirely based on their positions, so the first argument is bound to the first parameter and so on. The names doesn't really matter as far as the binding is concerned.

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Jonathan Sanders

Jonathan Sanders

Can you instantiate a variable within method parentheses?

1 Answer

andren

andren