Primitive types vs references exercises

`Coordinate2D` class

The exercises on this page use the Coordinate2D class. There are no tricks in the Coordinate2D class. Each method does what its header suggests.

Selected parts of Coordinate2D are shown below.

private int x, y;
public Coordinate2D(int initX, int initY)
public void setX(int newX) and public void setY(int newY)
public String toString() returns a String in the form: (x, y)

A link to the complete class is below.

Coordinate2D.java

For each exercise, give the output of the code segment.

Primitive exercise

int x = 5;
int y = 6;
x = y;
y = 7;
System.out.println(x);
System.out.println(y);

Primitive exercise solution & explanation

Reference exercise 1

Coordinate2D referenceOne = new Coordinate2D(1, 1);
Coordinate2D referenceTwo = new Coordinate2D(2, 2);
System.out.println(referenceOne);
System.out.println(referenceTwo);

Reference exercise 1 solution & explanation

Reference exercise 2

Coordinate2D referenceOne = new Coordinate2D(1, 1);
Coordinate2D referenceTwo = referenceOne;
System.out.println(referenceOne);
System.out.println(referenceTwo);

Reference exercise 2 solution & explanation

Reference exercise 3

Coordinate2D referenceOne = new Coordinate2D(1, 1);
Coordinate2D referenceTwo = referenceOne;
referenceOne.setX(3);
referenceTwo.setY(4);
System.out.println(referenceOne);
System.out.println(referenceTwo);

Reference exercise 3 solution & explanation

Reference exercise 4

Coordinate2D referenceOne = new Coordinate2D(1, 1);
Coordinate2D referenceTwo = referenceOne;

System.out.println(referenceOne);
System.out.println(referenceTwo);

referenceTwo = new Coordinate2D(2, 2);

System.out.println(referenceOne);
System.out.println(referenceTwo);

Reference exercise 4 solution & explanation

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