Leetcode No. 202 Question-happy number

To tell the truth, if you do not look at the answer of others, this problem I also have no train of thought, do not know the loop several times, also do not know the termination condition of the cycle, then know, " 2-6" This range of numbers are not happy number so there is a termination condition,n> 6 is the termination condition, and when n jumps into this range, it terminates the loop, and finally it can determine if it is happy number.

#include <stdio.h> #include <stdlib.h>bool ishappy (int n) {while    (n>6) {int sum=0;while (n) {sum+= (n% * (n%10); n/=10;} N=sum;} return n==1;} int main () {int m;while (scanf ("%d", &m)!=eof) {bool Flag=ishappy (m); if (flag) printf ("yes\n"); elseprintf ("no\n");} return 0;}

Leetcode No. 202 Question-happy number