Problem with constructors

[codyjava]

Hey my problem is I need to use constructors to assign values to variables from 1 class to another. So i have 3 different constructors 1 with no args 1 with 2 args and 1 with 4 (all args). I know its simple but how do iset values to variables in other classes use "set" methods if there is no args. I can't just reference it by using an object then calling the method.

Main class

public class Stock {
	
	// instance variables
	  private String symbol;
	  private String name;
	  private double previousClosingPrice;
	  private double currentPrice;


	//*********************** WRITE YOUR CONSTRUCTORS HERE ********************************
	  // constructors

public Stock(){
	symbol = null;
	name = null;
	previousClosingPrice = 0;
	currentPrice = 0;
}

public Stock(String newName,String newSymbol){
	name = newName;
	symbol = newSymbol;
}

public Stock(String newSymbol,String newName,Double newPreviousClosingPrice,Double newCurrentPrice){
	symbol = newSymbol;
	name = newName;
	previousClosingPrice = newPreviousClosingPrice;
	currentPrice = newCurrentPrice;
}

	//*************************************************************************************


	  // accessors (get methods)
	  public String getSymbol() {
	    return symbol;
	  }

	  public String getName() {
	    return name;
	  }

	  public double getPreviousClosingPrice() {
	    return previousClosingPrice;
	  }

	  public double getCurrentPrice() {
	    return currentPrice;
	  }

	  // mutators (set methods)
	  public void setSymbol( String newSymbol ) {
	    symbol = newSymbol;
	  }

	  public void setName( String newName ) {
	    name = newName;
	  }

	  public void setPreviousClosingPrice( double newPreviousPrice ) {
	    previousClosingPrice = newPreviousPrice;
	  }

	  public void setCurrentPrice( double newCurrentPrice ) {
	    currentPrice = newCurrentPrice;
	  }

	  // toString method
	  public String toString() {
	    return "Stock name: " + name + "\n" + "Symbol: " + symbol + "\n" + "Previous price: " + previousClosingPrice + "\n" + "Current price: " + currentPrice;
	  }

	  // domain specific method
	  public double computePercentChange() {
	    return (currentPrice - previousClosingPrice)/previousClosingPrice*100;
	  }
}

Tester class

public class TestStock {

	Stock stock1 = new Stock();
	
	stock1.setName("SUN");

	Stock stock2 = new Stock();
	
	
	Stock stock3 = new Stock("Mic","Microphone");
	stock3.setPreviousClosingPrice(50.0);
	stock3.setCurrentPrice(75.0);
	
	Stock stock4 = new Stock("Win","Windows");
	stock4.setPreviousClosingPrice(100.0);
	stock4.setCurrentPrice(200.0);
	
	Stock stock5 = new Stock();
	
	
	Stock stock6 = new Stock();

All of the times I use an object with a method from the other class I get an error of course. Any help is appreciated thanks.

[Zyril]

I don't really understand what your question is. You seem to answer it yourself:

All of the times I use an object with a method from the other class I get an error of course.

Ask yourself then why you try to use a method in a class, with an object that isn't of the same class?

[codyjava]

I know its wrong so what do I do how do I assign values to those variables (using constructors). I just need to know how to do it right basically

[Zyril]

Well, aren't you already doing it?

You have the following variables:

 private String symbol;
      private String name;
      private double previousClosingPrice;
      private double currentPrice;

They are being assigned when you use the contructor:

public Stock(String newSymbol,String newName,Double newPreviousClosingPrice,Double newCurrentPrice){
    symbol = newSymbol;
    name = newName;
    previousClosingPrice = newPreviousClosingPrice;
    currentPrice = newCurrentPrice;
}

Have you tried it?

      public static void main(String args[]){
    		Stock stockOne = new Stock("testSymbol", "testName", 9.5, 8.5);
    		System.out.println(stockOne.getCurrentPrice()); //This will print out 8.5
      }