int getsum(int x){

int sum=0;

while(x){

sum+=(x%10)*(x%10);

x=x/10;}

return sum;

}

bool isHappy(int n) {

if(n<=0)return false;

```
while(n!=1){
n=getsum(n);
if(n==4)return false;}//When the algorithm ends in a cycle of repeating numbers, this cycle always includes the number 4, so it is not even necessary to store previous numbers in the sequence:
return true;
```

}