interface

import java.util.*;

interface test{
	
	void square(int number);
}

class Arithmetic implements test{

	public void square(int number) {

		int square = number*number;
		System.out.println("The square is: " + square);

	}

}


public class ToTestInt {
	public static void main(String args[]) {
		Arithmetic num1 = new Arithmetic();
		num1.square(5);
	}

}

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//new problem 

import java.util.*;

interface A {

	int a = 5;
	int b = 7;
	void meth1();
	void meth2();

}

class MyClass implements A{

public void meth1(){
	int sum = a+b;
	System.out.println("the sum is: " + sum);
}

public void meth2(){
	int diff = a-b;
	System.out.println("the difference is: " + diff);
}
}

public class PlusMinus{
	public static void main(String args[])
	{
	MyClass obj1 = new MyClass();
	obj1.meth1();
	obj1.meth2();
	}
}