// A function that returns the value of a lambda expression - a closure.
// Problems! NO compiler warning issued.

#include <iostream>     
#include <string>
#include <functional>     // std::function

std::function<int(int)> f(const int seed0){
  int seed{seed0};        // Encapsualted local state

  return [&seed](int i){  // Returns a closure that captures seed. 
     seed++;              
     return i + seed;
  };

}

int main () {
  using namespace std;
  auto g = f(5);          // f(5) returns a function that accesses seed.
                          // seed dangles in the closure in g.

  for(int i = 1; i <= 5; i++)
    cout << "g(" << i << ") = " << g(i) << endl;    // Unpredicatable output
}