#include <iostream>
#include <functional>
#include <map>

void inputArray(int &size, int*& array, bool &was)
{
	std::cout << "Input array size: ";
	std::cin >> size;

	std::cout << "Input integer array of " << size << " size:" << std::endl;

	if (was)
	{
		delete[] array;
	}
	array = new int[size];
	was = true;

	for (int i = 0; i < size; ++i)
	{
		std::cout << "item " << i << ": ";
		std::cin >> array[i];
	}
}

void printArray(int &size, int*& array, bool &was)
{
	if (was)
	{
		std::cout << "Integer array [";
		std::cout << array[0];
		for (int i = 1; i < size; ++i)
		{
			std::cout << ", " << array[i];
		}
		std::cout << "]" << std::endl;
	}
}

void sumArray(int &size, int*& array, bool &was)
{
	if (was)
	{
		int result = 0;
		for (int i = 0; i < size; ++i)
		{
			result += array[i];
		}
		std::cout << "Sum of items is " << result << std::endl;
	}
}

void quit(int* array, bool &was)
{
	if (was)
	{
		delete[] array;
	}
}

class QuitEx{};

int main()
{
	bool was = false;
	int* array = 0;
	int size = 0;

	std::map<int, std::function<void()> > cmds;

	cmds[1] = [&size, &array, &was]()
	{
		inputArray(size, array, was);
	};

	cmds[2] = [&size, &array, &was]()
	{
		printArray(size, array, was);
	};

	cmds[3] = [&size, &array, &was]()
	{
		sumArray(size, array, was);
	};
	cmds[4] = [&array, &was]()
	{
		quit(array, was);
		throw QuitEx();
	};

	try
	{
		while (true)
		{
			int select;

			std::cin >> select;

			cmds[select]();
		}
	}
	catch (QuitEx const&)
	{
	}
    return 0;
}