Sum of two squares (hypotenuse-method)

main.cpp

#include <iostream>

int sqr(int n) {
  return n * n;
}

int main() {
  int r{};
  std::cin >> r;
  int x{};
  int y{};
  for (x = 0; sqr(x - 1) <= r; ++x) {}
  while (y <= x) {
    if (abs(r - sqr(x - 1) - sqr(y)) < abs(r - sqr(x + 1) - sqr(y)) &&
        abs(r - sqr(x - 1) - sqr(y)) < abs(r - sqr(x)     - sqr(y + 1))) {
      x -= 1;
    } else if (abs(r - sqr(x + 1) - sqr(y)) < abs(r - sqr(x - 1) - sqr(y)) &&
               abs(r - sqr(x + 1) - sqr(y)) < abs(r - sqr(x)     - sqr(y + 1))) {
      x += 1;
    } else {
      y += 1;
    }

    if ((sqr(x) + sqr(y)) == r && x * y != 0) {
      std::cout << x << " " << y << std::endl;
    }
  }
  return 0;
}