.png)
Interface in Java
Interface in Java
1.interface is an important element in java which is called reference type.
2.It is blueprint of class.
3.It is a collection of abstract method/function.
4.It is declared with interface keyword.
5.We can not create instance(object) of an interface.
6.We can not define function inside interface only can be declared,so it is the responsibility of derived class to implement the method/function of inetrface.
7.A class is extended by a class but an interface is implemented by a class.
Example
interface Geometry
{
void rectangle_area(int height,int width);
void square_area(int side);
void circle_area(float radius);
}
//implementing interface
class Easy implements Geometry
{
//implementing method of interface
public void rectangle_area(int height,int width)
{
int ar=height*width;
System.out.println("Area of rectangle="+ar);
}
//implementing method of interface
public void square_area(int side)
{
int ar=side*side;
System.out.println("Area of square="+ar);
}
//implementing method of interface
public void circle_area(float radius)
{
float ar=3.14f*radius*radius;
System.out.println("Area of circle="+ar);
}
public static void main(String[] args)
{
//creating instance of derived class
Easy obj=new Easy();
obj.rectangle_area(12, 13);
obj.square_area(12);
obj.circle_area(2.2f);
}
}
/*
### Output ###
Area of rectangle=156
Area of square=144
Area of circle=15.197601
*/
