Area - Interface

import java.io.*;
import java.util.Scanner;
interface area
{
float pi=3.14F;
void circle();
void square();
}
class imp implements area
{
public void circle()
{
System.out.print("enter the value of Radius:");
Scanner in=new Scanner(System.in);
float r=in.nextFloat();
float carea=pi*r*r;
System.out.println("\nArea of circle ="+carea);
}
public void square()
{
System.out.println("enter the value of side:");
Scanner in=new Scanner(System.in);
float x=in.nextFloat();
float sarea=x*x;
System.out.println("\n Area of circle:"+sarea);
}
}
class Interface
{
public static void main(String[] args)
{
imp obj=new imp();
obj.circle();
obj.square();
}
}