ranged based for loop in modern c++

#include <iostream>
#include <vector>
int main() {
 
  std::vector<int> int_list;
  int_list.push_back(1);
  int_list.push_back(2);
  int_list.push_back(3);
//   int int_list[4];
 
  for (int& x : int_list) {
    // This version of the loop will modify each item directly, by reference!
    x = 99;
  }
 
  for (int x : int_list) {
    std::cout << "This item has value: " << x << std::endl;
  }
 
  std::cout << "Everything was replaced with 99!" << std::endl;

  return 0;
}