#/*
 * highorder.cpp
 *
 *  Created on: 10.01.2013
 *      Author: trifon
 */

#include <iostream>
#include <cmath>
using namespace std;

int f(int x)
{
	return x + 2;
}

void swapi(int& x, int& y)
{
	int tmp = x;
	x = y;
	y = tmp;
}

double plus_op(double x, double y)
{
	return x + y;
}

double mult_op(double x, double y)
{
	return x * y;
}

typedef int(*next_function)(int);
typedef double(*term_function)(double);
typedef double(*operation)(double,double);

// plus1, mult2, mult_op, plus_op
double accumulate(operation op,
		          double base_value,
		          double a, double b,
		          term_function f,
		          next_function next)
{
	double s = base_value;
	for(int i = a; i <= b; i = next(i))
		s = op(s, f(i));
	return s;
}

int main1()
{
	typedef int number;
	typedef number new_number;
	number x = 2;
	for(number i = 0; i < x; i++)
		cout << i << endl;
	new_number y = 3;
	//swapi(x,y);
	cout << x << ' ' << y << endl;
	cout << x / y << endl;
	return 0;
}

typedef int matrix[10][10];

int g(matrix m)
{
	return m[0][0] + m[1][1];
}

int main2()
{
	matrix m = { { 1, 2, 3}, {4, 5, 6} };
	cout << m[1][2] << endl;

	typedef int **dpi;
	int* x = &m[0][1];
	dpi p = &x;
}

void h() {
	cout << "h()\n";
}

int plus1(int i) { return i + 1; }
int mult2(int i) { return i * 2; }

double sum(int n,
		   double(*f)(double),
		   int(*next)(int))
{
	double s = 0;
	for(int i = 1; i <= n; i = next(i))
		s += f(i);
	return s;
}

double sum2(int n,
		   double(*f)(double),
		   int(*next)(int))
{
	return accumulate(plus_op, 0, 1, n,
			          f, next);
}

double product(int n,
			   double(*f)(double),
			   int(*next)(int))
{
	double s = 1;
	for(int i = 1; i <= n; i = next(i))
		s *= f(i);
	return s;
}

double product2(int n,
		   double(*f)(double),
		   int(*next)(int))
{
	return accumulate(mult_op, 1, 1, n,
			          f, next);
}

// не можем да подадем на expterm x
// като параметър
// затова използваме глобална променлива
double X;

double id(double x)
{
	 return x;
}

double fact(double n)
{
	return accumulate(mult_op, 1,
			          1, n, id, plus1);
}

double expterm(double i)
{
	return pow(X,i)/fact(i);
}

double myexp(int n, double x)
{
	X = x;
	return accumulate(plus_op, 0,
			          0, n, expterm, plus1);
}

double N;
double K;

double binom_term(double i)
{
	return (N-K+i)/i;
}

double binom(int n, int k)
{
	N = n;
	K = k;
	return accumulate(mult_op, 1,
			          1, k, binom_term, plus1);
}

term_function choose_function(int n)
{
	switch(n)
	{
	case 1: return sin;
	case 2: return cos;
	case 3: return exp;
	case 4: return log;
	default: return NULL;
	}
}

const double EPS = 1E-10;
term_function F;

double derive_result(double x)
{
	return (F(x+EPS)-F(x))/EPS;
}

term_function derive(term_function f)
{
	F = f;
	return derive_result;
}


int main()
{
	cout << (void*)main << endl;
	cout << (void*)f << endl;

	void (*p)(int&,int&);
	p = swapi;

	cout << (void*)p << endl;
	cout << (void*)swapi << endl;

	int x = 1, y = 2;
	swapi(x, y);
	cout << x << ' ' << y << endl;
	p(x, y);
	cout << x << ' ' << y << endl;

	double (*op)(double) = sin;
	// func op;
	cout << (void*)op << endl;
	cout << op(0) << endl;
	op = cos;
	cout << (void*)op << endl;
	cout << op(0) << endl;
	op = NULL;
	cout << (void*)op << endl;

	typedef double (*math_fun)(double);
	math_fun op2 = sin;

	// !!! op = swapi;
	// !!! p = sin;

	typedef void (*simple_function)();
	simple_function q = h;
	q();
	void (*r)() = q;
	r();

	simple_function* qq = &q;
	(*qq)();
	void (**rr)() = &r;

	cout << sum(10, sin, plus1) << endl;
	cout << sum(10, cos, mult2) << endl;

	cout << accumulate(plus_op, 0, 1, 10,
			           sin, plus1)
			<< endl;
	cout << accumulate(plus_op, 0, 1, 10,
			           cos, mult2)
			<< endl;
	cout << fact(7) << endl;

	cout << myexp(20, 1) << endl;

	cout << binom(10, 3) << endl;

	int n;
	cout << "Изберете функция:";
	cin >> n;
	/*
	term_function f = choose_function(n);
	cout << f(1) << endl;
	*/
	cout << choose_function(n)(1) << endl;

	cout << exp(2) << endl;
	/*
	term_function f = derive(exp);
	cout << f(2) << endl;
	*/
	cout << derive(exp)(2) << endl;

	return 0;
}