// method return true if n is Happy Number int numSquareSum(int n) {  int num = 0;  while (n != 0) {  int digit = n % 10;  num += digit * digit;  n /= 10;  }  return num; } int isHappyNumber(int n) {  set<int> st;  while (1)  {  n = numSquareSum(n);  if (n == 1)  return true;  if (st.find(n) != st.end())  return false;  st.insert(n);  } } 

// method return true if n is Happy Number public static int numSquareSum(int n) {  int num = 0;  while (n != 0) {  int digit = n % 10;  num += digit * digit;  n /= 10;  }  return num; } static boolean isHappyNumber(int n) {  HashSet<Integer> st = new HashSet<>();  while (true) {  n = numSquareSum(n);  if (n == 1)  return true;  if (st.contains(n))  return false;  st.add(n);  } } // This code is contributed by Princi Singh 

# method return true if n is Happy Number def numSquareSum(n): num = 0 while(n): digit = n % 10 num = num + digit*digit n = n // 10 return num def isHappyNumber(n): st = set() while (1): n = numSquareSum(n) if (n == 1): return True if n not in st: return False st.insert(n) 

// Method return true if n is Happy Number static int numSquareSum(int n) {  int num = 0;  while (n != 0) {  int digit = n % 10;  num += digit * digit;  n /= 10;  }  return num; } static int isHappyNumber(int n) {  HashSet<int> st = new HashSet<>();  while (1) {  n = numSquareSum(n);  if (n == 1)  return true;  if (st.Contains(n))  return false;  st.Add(n);  } } // This code is contributed by 29AjayKumar 

<script> // method return true if n is Happy Number  function numSquareSum(n) {  let num = 0;  while (n !== 0) {  let digit = n % 10;  num += digit * digit;  n = Math.floor(n / 10);  }  return num;  }  let st = new Set();  while (1)  {  n = numSquareSum(n);  if (n == 1)  return true;  if (st.has(n))  return false;  st.add(n);  } } //This code is contributed by Mayank Tyagi </script> 

// C++ program to check a number is a Happy number or not #include    using namespace std; // Utility method to return sum of square of digit of n int numSquareSum(int n) {  int squareSum = 0;  while (n) {  squareSum += (n % 10) * (n % 10);  n /= 10;  }  return squareSum; } // method return true if n is Happy number bool isHappynumber(int n) {  int slow fast;  // initialize slow and fast by n  slow = fast = n;  do {  // move slow number by one iteration  slow = numSquareSum(slow);  // move fast number by two iteration  fast = numSquareSum(numSquareSum(fast));  } while (slow != fast);  // if both number meet at 1 then return true  return (slow == 1); } // Driver code to test above methods int main() {  int n = 13;  if (isHappynumber(n))  cout << n << ' is a Happy numbern';  else  cout << n << ' is not a Happy numbern'; } // This code is contributed by divyeshrabadiya07 

// C program to check a number is a Happy number or not #include  #include  // Utility method to return sum of square of digit of n int numSquareSum(int n) {  int squareSum = 0;  while (n) {  squareSum += (n % 10) * (n % 10);  n /= 10;  }  return squareSum; } // method return true if n is Happy number bool isHappynumber(int n) {  int slow fast;  // initialize slow and fast by n  slow = fast = n;  do {  // move slow number by one iteration  slow = numSquareSum(slow);  // move fast number by two iteration  fast = numSquareSum(numSquareSum(fast));  } while (slow != fast);  // if both number meet at 1 then return true  return (slow == 1); } // Driver code to test above methods int main() {  int n = 13;  if (isHappynumber(n))  printf('%d is a Happy numbern' n);  else  printf('%d is not a Happy numbern' n); } // This code is contributed by Sania Kumari Gupta // (kriSania804) 

// Java program to check a number is a Happy // number or not class GFG {   // Utility method to return sum of square of // digit of n static int numSquareSum(int n) {  int squareSum = 0;  while (n!= 0)  {  squareSum += (n % 10) * (n % 10);  n /= 10;  }  return squareSum; }   // method return true if n is Happy number static boolean isHappynumber(int n) {  int slow fast;    // initialize slow and fast by n  slow = fast = n;  do  {  // move slow number  // by one iteration  slow = numSquareSum(slow);    // move fast number  // by two iteration  fast = numSquareSum(numSquareSum(fast));    }  while (slow != fast);    // if both number meet at 1  // then return true  return (slow == 1); }   // Driver code to test above methods public static void main(String[] args) {  int n = 13;  if (isHappynumber(n))  System.out.println(n +   ' is a Happy number');  else  System.out.println(n +   ' is not a Happy number'); } } 

# Python3 program to check if a number is a Happy number or not # Utility method to return the sum of squares of digits of n def num_square_sum(n): square_sum = 0 while n: square_sum += (n % 10) ** 2 n //= 10 return square_sum # Method returns True if n is a Happy number def is_happy_number(n): # Initialize slow and fast pointers slow = n fast = n while True: # Move slow pointer by one iteration slow = num_square_sum(slow) # Move fast pointer by two iterations fast = num_square_sum(num_square_sum(fast)) if slow != fast: continue else: break # If both pointers meet at 1 then return True return slow == 1 # Driver Code n = 13 if is_happy_number(n): print(n 'is a Happy number') else: print(n 'is not a Happy number') 

// C# program to check a number // is a Happy number or not using System; class GFG { // Utility method to return  // sum of square of digit of n static int numSquareSum(int n) {  int squareSum = 0;  while (n!= 0)  {  squareSum += (n % 10) *   (n % 10);  n /= 10;  }  return squareSum; } // method return true if // n is Happy number static bool isHappynumber(int n) {  int slow fast;  // initialize slow and  // fast by n  slow = fast = n;  do  {    // move slow number  // by one iteration  slow = numSquareSum(slow);  // move fast number  // by two iteration  fast = numSquareSum(numSquareSum(fast));  }  while (slow != fast);  // if both number meet at 1  // then return true  return (slow == 1); } // Driver code public static void Main() {  int n = 13;  if (isHappynumber(n))  Console.WriteLine(n +   ' is a Happy number');  else  Console.WriteLine(n +   ' is not a Happy number'); } } // This code is contributed by anuj_67. 

<script> // Javascript program to check a number is a Happy // number or not // Utility method to return sum of square of // digit of n function numSquareSum(n) {  var squareSum = 0;  while (n!= 0)  {  squareSum += (n % 10) * (n % 10);  n = parseInt(n/10);  }  return squareSum; }   // method return true if n is Happy number function isHappynumber(n) {  var slow fast;    // initialize slow and fast by n  slow = fast = n;  do  {  // move slow number  // by one iteration  slow = numSquareSum(slow);    // move fast number  // by two iteration  fast = numSquareSum(numSquareSum(fast));    }  while (slow != fast);    // if both number meet at 1  // then return true  return (slow == 1); }   // Driver code to test above methods var n = 13; if (isHappynumber(n))  document.write(n +   ' is a Happy number'); else  document.write(n +   ' is not a Happy number');   // This code contributed by Princi Singh  </script> 

 // PHP program to check a number // is a Happy number or not // Utility method to return  // sum of square of digit of n function numSquareSum( $n) { $squareSum = 0; while ($n) { $squareSum += ($n % 10) * ($n % 10); $n /= 10; } return $squareSum; } // method return true if // n is Happy number function isHappynumber( $n) { $slow; $fast; // initialize slow  // and fast by n $slow = $n; $fast = $n; do { // move slow number // by one iteration $slow = numSquareSum($slow); // move fast number // by two iteration $fast = numSquareSum(numSquareSum($fast)); } while ($slow != $fast); // if both number meet at 1  // then return true return ($slow == 1); } // Driver Code $n = 13; if (isHappynumber($n)) echo $n  ' is a Happy numbern'; else echo n  ' is not a Happy numbern'; // This code is contributed by anuj_67. ?> 

// C++ program to check if a number is a Happy number or // not. #include    using namespace std; // Method - returns true if the input is a happy number else // returns false bool isHappynumber(int n) {  int sum = n x = n;  // This loop executes till the sum of square of digits  // obtained is not a single digit number  while (sum > 9) {  sum = 0;  // This loop finds the sum of square of digits  while (x > 0) {  int d = x % 10;  sum += d * d;  x /= 10;  }  x = sum;  }  if (sum == 7 || sum == 1)  return true;  return false; } int main() {  int n = 13;  if (isHappynumber(n))  cout << n << ' is a Happy number';  else  cout << n << ' is not a Happy number';  return 0; } // This code is contributed by Sania Kumari Gupta 

// C program to check if a number is a Happy number or // not. #include  #include  // Method - returns true if the input is a happy number else // returns false bool isHappynumber(int n) {  int sum = n x = n;  // This loop executes till the sum of square of digits  // obtained is not a single digit number  while (sum > 9) {  sum = 0;  // This loop finds the sum of square of digits  while (x > 0) {  int d = x % 10;  sum += d * d;  x /= 10;  }  x = sum;  }  if (sum == 7 || sum == 1)  return true;  return false; } int main() {  int n = 13;  if (isHappynumber(n))  printf('%d is a Happy number' n);  else  printf('%d is not a Happy number' n);  return 0; } // This code is contributed by Sania Kumari Gupta 

// This code is contributed by Vansh Sodhi. // Java program to check if a number is a Happy number or // not. class GFG {  // method - returns true if the input is a happy  // number else returns false  static boolean isHappynumber(int n)  {  int sum = n x = n;  // this loop executes till the sum of square of  // digits obtained is not a single digit number  while (sum > 9) {  sum = 0;  // this loop finds the sum of square of digits  while (x > 0) {  int d = x % 10;  sum += d * d;  x /= 10;  }  x = sum;  }  if (sum == 1 || sum == 7)  return true;  return false;  }  // Driver code  public static void main(String[] args)  {  int n = 13;  if (isHappynumber(n))  System.out.println(n + ' is a Happy number');  else  System.out.println(n  + ' is not a Happy number');  } } 

# Python3 program to check if a number is a Happy number or not. # Method - returns true if the input is # a happy number else returns false def isHappynumber(n): Sum x = n n # This loop executes till the sum # of square of digits obtained is # not a single digit number while Sum > 9: Sum = 0 # This loop finds the sum of # square of digits while x > 0: d = x % 10 Sum += d * d x = int(x / 10) x = Sum if Sum == 1 or Sum == 7: return True return False n = 13 if isHappynumber(n): print(n 'is a Happy number') else: print(n 'is not a Happy number') # This code is contributed by mukesh07. 

// C# program to check if a number // is a Happy number or not. using System; class GFG {  // Method - returns true if the input is  // a happy number else returns false  static bool isHappynumber(int n)  {  int sum = n x = n;  // This loop executes till the sum  // of square of digits obtained is  // not a single digit number  while (sum > 9) {  sum = 0;  // This loop finds the sum of  // square of digits  while (x > 0) {  int d = x % 10;  sum += d * d;  x /= 10;  }  x = sum;  }  if (sum == 1 || sum == 7)  return true;  return false;  }  // Driver code  public static void Main(String[] args)  {  int n = 13;  if (isHappynumber(n))  Console.WriteLine(n + ' is a Happy number');  else  Console.WriteLine(n + ' is not a Happy number');  } } // This code is contributed by 29AjayKumar 

<script> // This code is contributed by Vansh Sodhi. // javascript program to check if a number is a Happy number or not.  // method - returns true if the input is a happy  // number else returns false  function isHappynumber(n)  {  var sum = n x = n;  // this loop executes till the sum of square of  // digits obtained is not a single digit number  while(sum > 9)   {  sum = 0;  // this loop finds the sum of square of digits  while (x > 0)   {  var d = x % 10;  sum += d * d;  x /= 10;  }  x = sum;  }  if(sum == 1 || sum == 7)  return true;  return false; } // Driver code  var n = 13;  if (isHappynumber(n))  document.write(n +   ' is a Happy number');  else  document.write(n +   ' is not a Happy number');   // This code is contributed by 29AjayKumar  </script>