Check if a number is perfect square without finding square root in C++

Suppose a number is given, we have to check whether the number is a perfect square or not. We will not use the square root operation to check it. Suppose a number 1024 is there, this is a perfect square, but 1000 is not a perfect square. The logic is simple, we have to follow this algorithm to get the result.

Algorithm

isPerfectSquare(n) −

input − The number n

output − true, if the number is a perfect square, otherwise, false

begin
   for i := 1, i2 ≤ n, increase i by 1:
      if n is divisible by i, and n / i = i, then
         return true
   done
   return false
end

Example

Live Demo

#include <iostream>
using namespace std;
bool isPerfectSquare(int number) {
   for (int i = 1; i * i <= number; i++) {
      if ((number % i == 0) && (number / i == i)) {
         return true;
      }
   }
   return false;
}
int main() {
   int n = 1024;
   if(isPerfectSquare(n)){
      cout << n << " is perfect square number";
   } else {
      cout << n << " is not a perfect square number";
   }
}

Output

1024 is perfect square number