// A2.5.cpp : Defines the entry point for the console application.
//
// Please provide the definition of a function that accepts a vector of 
// pointers to functions with the signature int func(X &x), invokes each
// of the functions, and returns the sum of the computed values.

#include "stdafx.h"
#include <vector>
#include <iostream>
using namespace std;

class X {
public:
  X(int i) : val(i) { }
  int& value() { return val; }
private:
  int val;
};

int fun1(X &x) { return x.value(); }

int fun2(X &x) { return (x.value()*x.value()); }

//// answer /////////////////////////////////////////////////////
  typedef int(*fPtr)(X &x);

  int invoker(vector<fPtr> &vec, X &x) {
    int sum = 0;
    vector<fPtr>::iterator it;
    for(unsigned int i=0; i<vec.size(); ++i) {
      cout << "\n  invoking function pointer returns value " << vec[i](x);
      sum += vec[i](x);
    }
    return sum; 
  }
/////////////////////////////////////////////////////////////////

//// alternate answer ///////////////////////////////////////////
  int invoker2(vector<int(*)(X &x)> &vec, X &x)
  {
    vector<int(*)(X &x)>::iterator it;
    int sum = 0;  
    for(it = vec.begin(); it != vec.end(); ++it) {
      cout << "\n  invoking function pointer returns value " << (*it)(x);
      sum += (*it)(x);
    }
    return sum;
  }
/////////////////////////////////////////////////////////////////

int _tmain(int argc, _TCHAR* argv[])
{
  std::cout << "\n  Exam A2 - Question #5 "
            << "\n =======================\n";

  vector<fPtr> vec;
  vec.push_back(&fun1);
  vec.push_back(&fun2);
  cout << "\n  value returned by invoker = " << invoker(vec,X(5));
  cout << "\n\n";

  cout << "\n  value returned by invoker2 = " << invoker2(vec,X(3));
  cout << "\n\n";
  return 0;
}