Using Lambdas in C++: Listing 4

Printing odd elements from Listing 3, using lambda expressions.

int main()
{
  // a list of 20 integers
  list<int> l(20);

  // here's the lambda version of GenerateFibonacci::operator()() in Listing 3.
  // I replaced private variables penultimate_ and last_ with static ones, so they maintain
  // values between consecutive invocations.
  generate(begin(l), end(l), [] () {
    static int penultimate(0), last(1);
    int current = penultimate + last;

    penultimate = last;

    return last = current;
  });

  // likewise, we do the same with Listing 3 function printIfOdd(int).
  for_each(begin(l), end(l), [] (int n) {
  if (n%2)
    cout << n << " is odd." << endl;
  });

  return 0;
}

About the Author

Diego Dagum is a software architect and developer with more than 20 years of experience. He can be reached at email@diegodagum.com.