# Java – Calculating distance between two points in 3D

coordinatedistanceeuclidean-distancegetter-setterjava

My assignment is to create main class in which I initialize the value of any point to be at (0,0,0) and to be able to access and mutate all three values (x,y,z) individually. To do this I have used getters and setters. My next task is to create a method within my main class (which I shall call "distanceTo") that calculates the distance between two points.

How do I go about creating the method "`distanceTo`" that calculates the distance between two points by taking in the x,y,z coordinates ? I assume my answer will have something to do with `sqrt((x1-x2)^2+(y1-y2)^2+(z1-z2)^2)` but I do not know how I can write that in my method in my main class if my points are not defined until my second test point class

So far I only have two points, but I am looking for a more general answer (so that if I created three points, p1 p2 and p3, I could calculate the distance between p1 and p2 or the distance between p2 and p3 or the distance between p1 and p3.

My main class:

``````package divingrightin;

public class Point3d {

private double xCoord;
private double yCoord;
private double zCoord;

public Point3d(double x, double y, double z){
xCoord = x;
yCoord = y;
zCoord = z;
}

public Point3d(){
this (0,0,0);
}

public double getxCoord() {
return xCoord;
}
public void setxCoord(double xCoord) {
this.xCoord = xCoord;
}
public double getyCoord() {
return yCoord;
}
public void setyCoord(double yCoord) {
this.yCoord = yCoord;
}
public double getzCoord() {
return zCoord;
}
public void setzCoord(double zCoord) {
this.zCoord = zCoord;
}

//public double distanceTo(double xCoord, double yCoord, double zCoord ){

}
``````

My class with the test points:
package divingrightin;

``````public class TestPoints {

public static void main(String[] args) {

Point3d firstPoint = new Point3d();

firstPoint.setxCoord(2.2);
firstPoint.setyCoord(1);
firstPoint.setzCoord(5);

//System.out.println(firstPoint.getxCoord());

Point3d secondPoint = new Point3d();

secondPoint.setxCoord(3.5);
secondPoint.setyCoord(22);
secondPoint.setzCoord(20);

}

}
``````

#### Best Solution

As @Dude pointed out in the comments, you should write a method:

``````public double distanceTo(Point3d p) {
return Math.sqrt(Math.pow(x - p.getxCoord(), 2) + Math.pow(y - p.getyCoord(), 2) + Math.pow(z - p.getzCoord(), 2));
}
``````

Then if you want to get the distance between 2 points you just call:

``````myPoint.distanceTo(myOtherPoint);
//or if you want to get the distance to some x, y, z coords
myPoint.distanceTo(new Point3d(x,y,z);
``````

You could even make the method static and give it 2 points to compare:

``````public static double getDistance(Point3d p1, Point3d p2) {
return Math.sqrt(Math.pow(p1.getxCoord() - p2.getxCoord(), 2) + ...
}
``````

P.S. my first answer :)