LeeCode-Happy Number

Write an algorithm to determine if a number is "happy".

A happy number is a number defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1. Those numbers for which this process ends in 1 are happy numbers.

Example: 19 is a happy number

• 12 + 92 = 82
• 82 + 22 = 68
• 62 + 82 = 100
• 12 + 02 + 02 = 1

bool isHappy(int n){        if(n<0)        return false;        do     {        int sum=0;        while(n!=0)        {            sum=sum+(n%10)*(n%10);            n=n/10;        }                n=sum;        if(n==89)        {            return false;        }            if(n==1)        {            return true;        }    }     while (true);}