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Thread: Differences between local variables and instance variables

  1. #1
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    Default Differences between local variables and instance variables

    Hi I would really appreciate it if someone could briefly describe what the differences are between local variables and instance variables.
    Thank you.


  2. #2
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    Default Re: Differences between local variables and instance variables

    Consider the following code:
    class a
    {
    int a;
    void b()
    {
    int v;
    }}
    Here a is an instance variable. Every object created from this class will have its own copy of a. Instance variables are properties of an object. On the other hand, the variable v is a local variable that isn't a property of an object created from this class. Local variables are created whenever the method that declared them is invoked. Once control moves to the end of the method, local variables are destroyed.

    Now, consider the following test class
    class Test
    {
    public static void main(String args[])
    {
    a a1=new a1();
    a a2=new a2();
    a1.a=1;
    a2.a=2;
    System.out.println(a1.a+" "+a2.a); //the two objects a1 and a2 have their own values of a i.e a is the property of the instance of class a
    // This statement would give an error since v is a local variable and isn't a property of the object a1:   System.out.println(a2.v); 
    }
    }

  3. #3
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    Default Re: Differences between local variables and instance variables

    Thank you I really appreciate your comments.

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