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

const double PI = 3.141;
const int ROWS = 4;
const int COLUMNS = 4;

//function aka  method, routine, sub-routine, sub


//documentation
//modularization aka componentization  aka hiding the mess
//reuse

void getMatrixFromUser(int matrix[][COLUMNS])
{
	for(int row = 0; row < ROWS; row++)
	{
		cout << "  Row " << row + 1 << "? ";
		for(int column = 0; column < COLUMNS; column++)
		{
			cin >> matrix[row][column];
		}
	}
}
void displayMatrix(int matrix[][COLUMNS])
{
	for(int row = 0; row < ROWS; row++)
	{
		cout << "  Row " << row + 1 << ": ";
		for(int column = 0; column < COLUMNS; column++)
		{
			cout << matrix[row][column] << " ";
		}
		cout << endl;
	}
}

void matrixAdd(int matrix1[][COLUMNS], 
			   int matrix2[][COLUMNS], 
			   int answer[][COLUMNS])
{
	for(int row = 0; row < ROWS; row++)
	{
		for(int column = 0; column < COLUMNS; column++)
		{
			answer[row][column] = matrix1[row][column] + matrix2[row][column];
		}
	}
}

int userSelectedIndex(int matricesUsed)
{
	int result = 0;
	do
	{
		cin >> result; 
	}
	while(result <1 || result > matricesUsed);
	result--;
	return result;
}


void main()
{
	//literal or constant whole numbers
	int matrices[25][ROWS][COLUMNS];
	int matricesUsed = 0;

	int initialMatrices;
	do
	{
		cout << "How many initial matrices? ";
		cin >> initialMatrices;
	}
	while(initialMatrices < 1 || initialMatrices > 25);

	while(matricesUsed < initialMatrices)
	{
		getMatrixFromUser(matrices[matricesUsed]);
		matricesUsed++;
	}

	char menuOption;
	cin >> menuOption;
	
	int firstMatrix;
	int secondMatrix;
	
	switch(menuOption)
	{
		case '+':
			cout <<  "First matrix for +?" ;
			firstMatrix = userSelectedIndex(matricesUsed);
			cout <<  "Second matrix for +?" ;
			secondMatrix = userSelectedIndex(matricesUsed);
			matrixAdd(matrices[firstMatrix], matrices[secondMatrix], matrices[matricesUsed]);
			matricesUsed++;
			break;
		case '-':
			cout <<  "First matrix for -?" ;
			firstMatrix = userSelectedIndex(matricesUsed);
			cout <<  "Second matrix for -?" ;
			secondMatrix = userSelectedIndex(matricesUsed);
			matrixSubtract(matrices[firstMatrix], matrices[secondMatrix], matrices[matricesUsed]);
			matricesUsed++;
			break;	}


	displayMatrix(matrices[2]);

}