// 
// arrayexample.cpp
//
// program to demonstrate passing multidimensional arrays
// into and out of functions, and working with them using
// nested for loops
//

#include <stdlib.h>
#include <iostream.h>

// Maximum array size
const int NUMROWS = 10;
const int NUMCOLS = 20;

// Function prototypes
void GetRowsAndCols(int& rows, int& cols);
void ReadArray(int rows, int cols, int A[][NUMCOLS]);
void WriteArrayRows(int rows, int cols, const int A[][NUMCOLS]);
void WriteArrayCols(int rows, int cols, const int A[][NUMCOLS]);

void main()
{

	int rows, cols;
	int A[NUMROWS][NUMCOLS];

	GetRowsAndCols(rows, cols);
	cout << endl;

	ReadArray(rows, cols, A);
	cout << endl;

	cout << "Row by row output: " << endl;
	WriteArrayRows(rows, cols, A);
	cout << endl << endl;

	cout << "Column by column output: " << endl;
	WriteArrayCols(rows, cols, A);
	cout << endl;


}

//
// void GetRowsAndCols(int& rows, int& cols)
//
// Purpose: get the number of rows and columns to use from the array
//			requires a valid value for rows and for columns
//
// Parameters:
//			rows and cols: output the number of rows and columns input by user
//
void GetRowsAndCols(int& rows, int& cols)
{
	// get a valid value for rows
	do {
		cout << "How many rows do you want to fill in? "
			 << "(0 < rows <= " << NUMROWS << ") ";
		cin >> rows;
	}
	while (rows < 1 || rows > NUMROWS);
	
	// get a valid value for columns   
	do {
		cout << "How many columns do you want to fill in? "
			 << "(0 < rows <= " << NUMCOLS << ") ";
		cin >> cols;
	}
	while (cols < 1 || cols > NUMCOLS);
}


// 
// void ReadArray(int rows, int cols, int A[][NUMCOLS])
//
// Purpose: read in values from a user to fill in 
//			a rows X cols section of an array 
//
// Parameter:
//			rows, cols: the number of rows and columns of the array
//				to fill in
//			A: array to contain (and return) the values read in
//
void ReadArray(int rows, int cols, int A[][NUMCOLS])
{
	for (int i = 0; i < rows; i++) {
		cout << "Enter " << cols << " numbers for row number " << i << " ";
		for (int j = 0; j < cols; j++) 
			cin >> A[i][j];
	}
}

// 
// void WriteArrayRows(int rows, int cols, const int A[][NUMCOLS])
//
// Purpose: print out a rows X cols section of an array
//			row by row
//
// Parameter:
//			rows, cols: the number of rows and columns of the array
//				to output
//			A: array to output
//
void WriteArrayRows(int rows, int cols, const int A[][NUMCOLS])
{
	for (int i = 0; i < rows; i++) {
		for (int j = 0; j < cols; j++) 
			cout << A[i][j] << "  ";	// Did you remember the space?
		cout << endl;					// Did you remember the newline?
	}
}

// 
// void WriteArrayCols(int rows, int cols, const int A[][NUMCOLS])
//
// Purpose: print out a rows X cols section of an array
//			column by column
//
// Parameter:
//			rows, cols: the number of rows and columns of the array
//				to output
//			A: array to output
//
void WriteArrayCols(int rows, int cols, const int A[][NUMCOLS])
{
	for (int i = 0; i < cols; i++) {	// For each column....
		for (int j = 0; j < rows; j++)	// For each row of the column...
			cout << A[j][i] << "  ";	// Did you remember the space?
		cout << endl;					// Did you remember the newline?
	}
}