#include <iostream>

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 Command
{
public:
	virtual void handle() = 0;
};

class Input : public Command
{
	int& size;
	int*& array;
	bool& was;
public:
	Input(int& _size, int*& _array, bool& _was)
		:size(_size), array(_array), was(_was)
	{}

	virtual void handle()
	{
		inputArray(size, array, was);
	}
};

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

	while (true)
	{
		int select;

		std::cin >> select;

		switch (select)
		{
		case 1:
		{
			Input command(size, array, was);
			command.handle();

			break;
		}
		case 2:
		{
			printArray(size, array, was);

			break;
		}
		case 3:
		{
			sumArray(size, array, was);

			break;
		}
		case 4:
		{
			quit(array, was);

			return 0;
		}
		}
	}
    return 0;
}