Java Interface-HackerRank Solution

A Java interface can only contain method signatures and fields. The interface can be used to achieve polymorphism. In this problem, you will practice your knowledge on interfaces.

You are given an interface AdvancedArithmetic which contains a method signature int divisor_sum(int n). You need to write a class called MyCalculator which implements the interface.

divisorSum function just takes an integer as input and return the sum of all its divisors. For example divisors of 6 are 1, 2, 3 and 6, so divisor_sum should return 12. The value of n will be at most 1000.

Read the partially completed code in the editor and complete it. You just need to write the MyCalculator class only. Your class shouldn't be public.

Sample Input 

 6

Sample Output

 I implemented: AdvancedArithmetic
 12

Solution 

 import java.util.*;
 interface AdvancedArithmetic{
    int divisor_sum(int n);
 }

 //Write your code here
 class MyCalculator implements AdvancedArithmetic{
   public int divisor_sum(int n){
          int sum=0;
         if(n<=1000){
          for(int i=1;i<=n;i++){
            if(n%i==0){
              sum=sum+i;
             }
          }
       }  
   return sum;
  }
 }

 class Solution{
 public static void main(String []args){
            MyCalculator my_calculator = new MyCalculator();
            System.out.print("I implemented: ");
            ImplementedInterfaceNames(my_calculator);
            Scanner sc = new Scanner(System.in);
            int n = sc.nextInt();
            System.out.print(my_calculator.divisor_sum(n) + "\n");
            sc.close(); }
/*
* ImplementedInterfaceNames method takes an object and prints the name of the interfaces it implemented
*/
           static void ImplementedInterfaceNames(Object o){
           Class[] theInterfaces = o.getClass().getInterfaces();
           for (int i = 0; i
           String interfaceName = theInterfaces[i].getName();
           System.out.println(interfaceName);
              }
      }
 }

In Java, an interface is a blueprint or template of a class. It is much similar to the Java class but the only difference is that it has abstract methods and static constants.

There can be only abstract methods in an interface, that is there is no method body inside these abstract methods. The class that implements the interface should be abstract, otherwise, we need to define all the methods of the interface in the class.