variables not found with OOP

[Ben Hultin]

I am trying out my hand at OOP and I have run into a problem regarding variables not found between two files (the driver and the driven class).

driver class

   

import java.util.*;

public class HultinBenWeek6Prog
{
    public static void main (String[] args)
    {
    cat myCat1 = new cat();
	cat myCat2 = new cat();
	cat myCat3 = new cat();

    Scanner input = new Scanner(System.in);
	

	System.out.println("Please enter info about your first cat.");
	myCat1.input();
	System.out.println("Please enter info about your second cat.");
	myCat2.input();
	System.out.println("Please enter info about your third cat.");
	myCat3.input();

    myCat1.set(name, age, weight);
    myCat1.setBreed(breed);
	myCat1.setDeclawed(declawed);
	myCat1.setName(name);
	myCat1.setAge(age);
	myCat1.setWeight(weight);
	
    System.out.println("name: " + myCat1.getName()); // null
    System.out.println("breed: " + myCat1.getBreed()); // tabby
	System.out.println("declawed: " + myCat1.getDeclawed()); // true
	System.out.println("age: " + myCat1.getAge()); // 0
	System.out.println("weight: " + myCat1.getWeight()); // 0.0

    }

} 


 

driven class

  

import java.util.*;

public class cat
{
	Scanner input = new Scanner(System.in);

    private String breed;
    boolean declawed;
    private String name;
    private int age;//in years
    private double weight;//in pounds

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

    public void setBreed(String newBreed)
    {
        breed = newBreed; //age and weight are unchanged.
    }
	
	public void setAge(int newAge)
    {
        age = newAge; 
    }
	
	public void setWeight(double newWeight)
    {
        weight = newWeight; 
    }
	
	public void setDeclawed(boolean newDeclawed)
    {
        declawed = newDeclawed;
    }

    public String getBreed( )
    {
        return breed;
    }
	
	public String getName()
	{
		return name;
	}
	
	public int getAge()
	{
			return age;
	}
	
	public double getWeight()
	{
		return weight;
	}
	
	public boolean getDeclawed()
	{
		return declawed;
	}
	
	public void input() {
	
    System.out.println("Enter a cats name:");
    String name = input.next();

    System.out.println("Enter cats age:");
    int age = input.nextInt();

    System.out.println("Enter cats weight:");
    double weight = input.nextDouble();

    System.out.println("Enter cats breed:");
    String breed = input.next();

    System.out.println("Is your cat declawed? True or False");
    boolean declawed = input.nextBoolean();
	
	}

    public void set(String name, int age, double weight)
    {
    //put appropriate code here
    }



} 


  

The errors I am getting refer to the lines of code in the driver class at the bottom

HultinBenWeek6Prog.java:117: cannot find symbol
symbol : variable name
location: class HultinBenWeek6Prog
myCat1.set(name, age, weight);
^
HultinBenWeek6Prog.java:117: cannot find symbol
symbol : variable age
location: class HultinBenWeek6Prog
myCat1.set(name, age, weight);
^
HultinBenWeek6Prog.java:117: cannot find symbol
symbol : variable weight
location: class HultinBenWeek6Prog
myCat1.set(name, age, weight);
^
HultinBenWeek6Prog.java:118: cannot find symbol
symbol : variable breed
location: class HultinBenWeek6Prog
myCat1.setBreed(breed);
^
HultinBenWeek6Prog.java:119: cannot find symbol
symbol : variable declawed
location: class HultinBenWeek6Prog
myCat1.setDeclawed(declawed);
^
HultinBenWeek6Prog.java:120: cannot find symbol
symbol : variable name
location: class HultinBenWeek6Prog
myCat1.setName(name);
^
HultinBenWeek6Prog.java:121: cannot find symbol
symbol : variable age
location: class HultinBenWeek6Prog
myCat1.setAge(age);
^
HultinBenWeek6Prog.java:122: cannot find symbol
symbol : variable weight
location: class HultinBenWeek6Prog
myCat1.setWeight(weight);
^
8 errors

[Rok Štelcer]

Hi,

Before starting with OOP in any language, you should master the basis or language fundamentals per se first.

Hm ... where should I start.
OK, following has to be corrected:

class name should always start with an uppercase ... naming convention.
Check the following ling: http://java.sun.com/docs/codeconv/html/CodeConventions.doc8.html

cat.input method stores all results in local vars (not class member vars).
Meaning that all results will be lost after the method completes (local scope)

No need for Scanner class in HultinBenWeek6Prog ... has no functionality

As I already mentioned before, change the input method.
For example:
String name = input.next();
change with
setName( input.next() );
This how, you'll store the results in member vars ... meaning they will be available as long as the object lives (or particular member is not changed/modified)

WRONG:
# myCat1.set(name, age, weight);
# myCat1.setBreed(breed);
# myCat1.setDeclawed(declawed);
# myCat1.setName(name);
# myCat1.setAge(age);
# myCat1.setWeight(weight);
vars like name, age, weight, etc. are declared in class Cat not in HultinBenWeek6Prog ... beside this, they are private (java access modifier) --> encapsulation ... well, except declawed.
Remove the all above lines. Or you can leave them in order to demonstrate the member modification ...

I think, this is all.


Regards,
Rok