Learning basics about objects

Question

public class Vector {
 private final double deltaX,deltaY;
 public Vector(double deltaX, double deltaY) {
 this.deltaX = deltaX;
 this.deltaY = deltaY;
 public Vector plus(Vector(a, b)){
 return new Vector(this.deltaX+a,this.deltaY+b);
 }

why does this not work when I am trying to create a method to add a new vector to my existing one? i am defining deltaX as the horizontal component and deltaY as the vertical.

• user2864740: Java does not support value decomposition. Each parameter must be taken in as a single object/value.

Answer 1

You aren't using the correct syntax. Your method should be:

public Vector plus(Vector other) {
 return new Vector(this.deltaX + other.deltaX, this.deltaY + other.deltaY);
}

That way, somebody can pass Vector instances into the method.

Answer 2

Should be:

public Vector plus(Vector v) {
 return new Vector(this.deltaX + v.getDeltaX(),
 this.deltaY + v.getDeltaY());
}

Where you define those getter methods. Alternately, make deltaX and deltaY public and access them directly from v.