This is the same program I asked about last time, but this time I only get zeros for the areas and perimeters and stuff. I'm pretty sure it's something I left out when constructing the square... Here's what I have.

public class Square {
 

  private double side;
  private double perimeter;
  private double area;
  
  
  
 
  public Square(int x){
   
  side = side;
   
  }
  
  public double getSide(){
   
    
    return side;
  }
  
  
 
  public String toString(){
    String s = side + "---";
    s = s + side;
    s = s + area;
    s = s + perimeter;
  return s; 
    
  }
  
  
  public double calculateArea(){
    
    return side*side;
  }
  

  public double calculatePerimeter(){
   
    return side*4;
  }
}

Sooooo close to being done ><

This post has been edited by William_Wilson: 6 Oct, 2008 - 10:48 AM

you never calculate those values.
Add to your constructor:

perimeter = calculatePerimeter();
area = calculateArea();

and you are good to go.


EDIT:
just for future knowledge, when you put s = s + side; this is the same as s += side;. Though you will probably want to add spaces in the String too, but it still works the same way.

This post has been edited by William_Wilson: 6 Oct, 2008 - 10:52 AM

First off, post your code in a code box.

Bellow I have posted the corrected code. It was very close, just a few changes, I commented everything I changed, anything I deleted I commented out and put and "X" right after the slashes. IE //X: perimeter = 4; I also explained why I did everything. Make sure you don't just use this code. Make sure you understand why.

public class Square {
    private double side;
    //private double perimeter; //not used
    //private double area; //not used
    
    public Square(int x){
        side = x; //X: side = side; //this does nothing
    }
    
    public String dataToString(){ //X: toString(){ //don't use "toString()," it can end up overriding a class method
        String s = ""; //X: "---" //start with it blank
        String endl = "\n"; //new line variable
        s += endl + "Side:      " + getSide(); //X:+ side; //you never assigned a value to this variable, that's why it appeared as a 0
        s += endl + "Area:      " + getArea();  //X:+ area; //you never assigned a value to this variable, that's why it appeared as a 0
        s += endl + "Perimeter: " + getPerimeter(); //X:+ perimeter; //you never assigned a value to this variable, that's why it appeared as a 0
        return s;
    }

    public double getSide(){
        return side;
    }
    
    public double getArea(){ //X:calculateArea(){ //stick with the root "get", consistency makes usage easier. it is also less to type
        return side*side;
    }
    
    public double getPerimeter(){ //X:calculatePerimeter(){ //stick with the root "get", consistency makes usage easier. it is also less to type
        return side*4;
    }
}

I wrote a test class. I'm sure you did too, but it likely isn't compatible anymore.

//import the scanner
import java.util.Scanner;

public class TestSquare{
    //create variables
    public static Scanner reader = new Scanner(System.in);
    public static int num;
    
    public static void main(String[] args){
        //tell the user what to do
        System.out.print("Enter the measurement of square side: ");
        //get user data
        num = reader.nextInt();
        //instantiate the class
        Square square = new Square(num);
        //use the classes output method
        System.out.print(square.dataToString());
    }
}

If you have anymore questions or don't understand something, just let me know.

Good Luck!

This post has been edited by stauffski: 6 Oct, 2008 - 10:57 AM

Gahhh thanks again you guys! I feel like I really understand that one now. I'm gonna see if I can do the next one completely on my own... Just me and my Java book

public String dataToString(){ //X: toString(){ //don't use "toString()," it can end up overriding a class method

the toString method overrides the Object class' toString method, every class inherits from the Object class.

So you can use the toString method provided that another super class does not implement this method, which in this case the square class does not have any super classes(beside Object) so overiding this method is fine.

So if you override this method then the statement
System.out.print(square.dataToString());
in the Test class can be simplified to
System.out.print(square);
Where the toString method is automatically called.