leap_year.cpp

#include <iostream>

int main() {
  int yearInput;
  std::cout << "Please input a year:\n";
  std::cin >> yearInput;

  if (yearInput > 1000 || yearInput < 9999){
    if (yearInput % 4 == 0 && yearInput % 100 != 0 || yearInput % 400 == 0){
      std::cout << "The year " << yearInput << " is a leap year.\n";
    }else {
      std::cout << "The year " << yearInput << " is not a leap year.\n";
    }
  }else {
      std::cout << yearInput << " is an invalid year\n";
    }
}