// Iterators.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <algorithm>

using namespace std;

class ForwardString:public string
{
	public:
		ForwardString(_TCHAR *pString):string(pString)
		{
		}
};

class ReverseString:public string
{
	public:
		ReverseString(_TCHAR *pString):string(pString)
		{
		}

		bool traverse()
		{
			for (reverse_iterator i=this->rbegin();i!=this->rend();++i)
				if (this->processItem(*i))
					return true;
			return false;
		}

	protected:
		virtual bool processItem(_TCHAR c)
		{
			cout << c;
			return false;
		}
};

static void testForward1()
{
	string message(_T("Hello, world!"));

	// Without the cast, the following error message is produced:
	// error C2664: 'std::copy': cannot convert parameter 3 from 'std::ostream' to 'std::ostream'
	copy(message.begin(),message.end(),(ostream_iterator<_TCHAR>) cout);
	cout << endl;
}

static void testForward2()
{
	string message(_T("Hello, world!"));

	// copy utility amounts to approximately the following code
	string::iterator first=message.begin();
	string::iterator last=message.end();
	ostream_iterator<_TCHAR> dest=cout;

	for (;first!=last;++dest,++first)
		*dest=*first;
	cout << endl;
}

static void testForward3()
{
	string message(_T("Hello, world!"));

	// This is an example of an external iterator
	for (string::iterator i=message.begin();i!=message.end();++i)
		cout << *i;
	cout << endl;
}

static void testForward4()
{
	ForwardString message(_T("Hello, world!"));

	for (string::iterator i=message.begin();i!=message.end();++i)
		cout << *i;
	cout << endl;
}

static void testReverse1()
{
	string message(_T("Hello, world!"));

	// This is an example of an external iterator
	for (string::reverse_iterator i=message.rbegin();i!=message.rend();++i)
		cout << *i;
	cout << endl;
}

static void testReverse2()
{
	ReverseString message(_T("Hello, world!"));

	message.traverse();
	cout << endl;
}

class SinglePalindromeTest
{
	protected:
		string::reverse_iterator reverseIterator;

	public:
		SinglePalindromeTest(string &aString):reverseIterator(aString.rbegin())
		{
		}

		bool operator()(_TCHAR c)
		{
			bool mismatch=(*reverseIterator!=c);

			++reverseIterator;
			return mismatch;
		}
};

static bool testPalindrome1()
{
	string message("poordanisinadroop");
	
	return find_if(message.begin(),message.end(),SinglePalindromeTest(message))==message.end();
}

static bool testPalindrome2()
{
	bool isPalindrome=true;
	string message("drawalevelaward");
	string::iterator forwardIterator(message.begin());
	string::reverse_iterator reverseIterator(message.rbegin());

	while (forwardIterator!=message.end() && reverseIterator!=message.rend())
	{
		if (*forwardIterator!=*reverseIterator)
			isPalindrome=false;
		++forwardIterator;
		++reverseIterator;
	}
	return isPalindrome;
}

template <class Container> bool isPalindrome(Container &container)
{
	Container::iterator forwardIterator(container.begin());
	Container::reverse_iterator reverseIterator(container.rbegin());

	while (forwardIterator!=container.end() && reverseIterator!=container.rend())
	{
		if (*forwardIterator!=*reverseIterator)
			return false;
		++forwardIterator;
		++reverseIterator;
	}
	return true;
}

static bool testPalindrome3()
{
	return isPalindrome<string>(string("madamimadam"));
}

static void testReverse()
{
	testReverse1();
	testReverse2();
}

static void testForward()
{
	testForward1();
	testForward2();
	testForward3();
	testForward4();
}

static void testPalindrome()
{
	cout << (testPalindrome1() ? "true" : "false") << endl;
	cout << (testPalindrome2() ? "true" : "false") << endl;
	cout << (testPalindrome3() ? "true" : "false") << endl;
}

int _tmain(int argc,_TCHAR *argv[])
{
	testForward();
	testReverse();
	testPalindrome();
	return 0;
}