//Happy numbers are the numbers when you recursively add the square of the digits, it ends to 1. // eg: 7 -> 49 -> 97 -> 130 -> 10 ->1 So 7 is happy number // similarly 4 is not happy number static void Main(string[] args) { HappyNumber checkHappy = new HappyNumber(); //Recursive Console.WriteLine($"Is 7 happy: {checkHappy.IsHappyRecursive(7)}"); Console.WriteLine($"Is 4 happy: {checkHappy.IsHappyRecursive(4)}"); Console.WriteLine($"Is 9 happy: {checkHappy.IsHappyRecursive(9)}"); Console.WriteLine($"Is 13 happy: {checkHappy.IsHappyRecursive(13)}"); //Iterative Console.WriteLine($"Is 9 happy: {checkHappy.IsHappyIterative(9)}"); Console.WriteLine($"Is 10 happy: {checkHappy.IsHappyIterative(10)}"); Console.WriteLine($"Is 13 happy: {checkHappy.IsHappyIterative(13)}"); Console.WriteLine($"Is 19 happy: {checkHappy.IsHappyIterative(19)}"); //No extra space Console.WriteLine($"Is 7 happy: {checkHappy.IsHappyWithNoExtraSpace(7)}"); Console.WriteLine($"Is 9 happy: {checkHappy.IsHappyWithNoExtraSpace(9)}"); Console.WriteLine($"Is 13 happy: {checkHappy.IsHappyWithNoExtraSpace(13)}"); Console.WriteLine($"Is 17 happy: {checkHappy.IsHappyWithNoExtraSpace(17)}"); }