Editing Instance variable (section)

==Examples==

=== C++ ===
<syntaxhighlight lang="cpp">
struct Request {

    static int count1; // variable name is not important
    int number;

    Request() {
        number = count1; // modifies the instance variable "this->number"
        ++count1; // modifies the class variable "Request::count1"
    }

};

int Request::count1 = 0;
</syntaxhighlight>

In this [[C++]] example, the instance variable <code>Request::number</code> is a copy of the [[class variable]] <code>Request::count1</code> where each instance constructed is assigned a sequential value of <code>count1</code> before it is [[increment operator|incremented]]. Since <code>number</code> is an instance variable, each <code>Request</code> object contains its own distinct value; in contrast, there is only one object <code>Request::count1</code> available to all class instances with the same value.

=== Java ===
<syntaxhighlight lang="java">
//Example.java

class Example {
    public int x = 0;
    
    public void setX(int newValue) {
        this.x = newValue;
    }
}

//Main.java

class Main {
    public static void main(String[] args) {
        Example example1 = new Example();
        Example example2 = new Example();
        
        //We can set the value of x by itself, as the variable is public
        example1.x = 10;
        
        assert example1.x == 10;
        assert example2.x ==  0;
        
        //As setX is an instance method, it can also access the variable
        example2.setX(-10);
        
        assert example1.x ==  10;
        assert example2.x == -10;
    }
}
</syntaxhighlight>

In this [[Java (programming language)|Java]] example, we can see how instance variables can be modified in one instance without affecting another.

=== Python ===
<syntaxhighlight lang="python">
class Dog:
    def __init__(self, breed):
        self.breed = breed # instance variable

# dog_1 is an object
# which is also an instance of the Dog class
dog_1 = Dog("Border Collie")
</syntaxhighlight>In the above [[Python (programming language)|Python]] code, the instance variable is created when an argument is parsed into the instance, with the specification of the breed positional argument.