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A point consists of a pair of numbers, (x, y).

Description of a Class

A description of the class Point is found in the Java documentation. Look at the documentation on your hard disk or on the web to see it. You will see something like the following:

Class Point   

. . .

// Field Summary
int x; 
int y; 

// Constructor Summary
Point();                 // creates a point at (0,0)
Point(int  x, int  y);   // creates a point at (x,y)
Point( Point pt );       // creates a point at the location given in pt

// Method Summary
boolean equals(Object  obj);  // checks if two point objects hold equivalent data
void move(int  x, int  y);    // changes the (x,y) data of a point object 
String toString();            // returns character data that can be printed

(I've left out some methods we won't be using.)

The documentation shows the data and methods contained in Point objects, the constructors that create such objects. Variables are sometimes called fields (as is done here). The two variables are named x and y and are of type int.


There are three constructors listed for Point. Each one creates the same type of object. What is the difference between the constructors?