// Demonstrating use of replace and replace_if algorithms with list


#include <list.h>
#include <algo.h>
#include <assert.h>

void show_int (int x)
{
  cout << x << " ";
}

// sample PREDICATE functions -- take a parameter of same
// type as the container, and pass back boolean if condition is true

// Predicate works as a "filter" or "test" that can be applied on 
// STL containers with considerable convenience

// a function object is a class which overloads the
// function call () operator
// Like a function, you can "call" a function object
// It can be used as a predicate, etc. in STL algorithm calls
// A function object is MORE powerful than a function
// because you can package additional data with an object

class greater_than_x
{
public:
  greater_than_x(int v) { val=v; }
  bool operator() (int a) { return a > val ? true : false ; }
private:
  int val;
};


int main()
{
  cout << "Demonstrating count_if and find_if with lists." << endl;

  list<int> list2;

  // populating the list using "push_back"
  list2.push_back(89);
  list2.push_back(99);
  list2.push_back(89);
  list2.push_back(69);
  list2.push_back(59);
  list2.push_back(89);
  list2.push_back(89);
  list2.push_back(49);

  cout << "LIST2 Elements (before replacements) : " << endl;
  for_each(list2.begin(), list2.end(), show_int);
  cout << endl;

  replace(list2.begin(), list2.end(), 89, 400);
  cout << "LIST2 Elements (first replacement)   : " << endl;
  for_each(list2.begin(), list2.end(), show_int);
  cout << endl;

  replace_if(list2.begin(), list2.end(), greater_than_x(70), 200);
  cout << "LIST2 Elements (second replacement)  : " << endl;
  for_each(list2.begin(), list2.end(), show_int);
  cout << endl;

}