Objects as Parameters

Objects as Parameters

The object can be passed to a method as an argument. Using dot operator the object's value can be accessed. Such a method can be represented syntactically as -

Data Type name_of_method(object_name)

{

//body of method

}

Following is a sample Java program in which the method area is defined. The parameter passed to this method is an object.

Java Program[ ObjDemo.java]

public class ObjDemo {

int height;

int width;

ObjDemo(int h,int w)

{

height=h;

width=w;

}

void area(ObjDemo o)

{

int result (height+o.height)*(width+o.width);

System.out.println("The area is "+result);

}

}

class Demo {

public static void main(String args[])

{

ObjDemo obj1 = new ObjDemo (2,3);

ObjDemo obj2= new ObjDemo(10,20);

obj1.area(obj2);

}

}

Output

F:\test>javac ObjDemo.java

F:\test>java Demo

The area is 276

Program Explanation

• The method, area has object obj2 as argument. And there is another object named obj1 using which the method area is invoked. Inside the method area, the height and width values of invoking object are added with the height and width values of the object to be passed.

• When an object needs to be passed as a parameter to the function then constructor is built. Hence we have to define constructor in which the values of the object are used for initialization.