What if C++ had no built-in facility for two-dimensional arrays? It is

possible to emulate them yourself with wrapper functions around a onedimensional

array. The basic idea is shown below. Consider the following

two-dimensional array:

int matrix[2][3];

It can be visualized as a table:

matrix[0][0] matrix[0][1] matrix[0][2]

matrix[1][0] matrix[1][1] matrix[1][2]

The two-dimensional array can be mapped to storage in a one-dimensional

array where each row is stored in consecutive memory locations (your

compiler actually does something very similar to map two-dimensional

arrays to memory).

int matrix1D[6];

matrix[0][0] matrix1D[0][1] matrix1D[0][2] matrix1D[1][0] matrix1D[1][1] matrix1D[1][2]

Here, the mapping is as follows:

matrix[0][0] would be stored in matrix1D[0]

matrix[0][1] would be stored in matrix1D[1]

matrix[0][2] would be stored in matrix1D[2]

matrix[1][0] would be stored in matrix1D[3]

matrix[1][1] would be stored in matrix1D[4]

matrix[1][2] would be stored in matrix1D[5]

Based on this idea, complete the definitions for the following functions.

int* create2DArray(int rows, int columns);

This creates a one-dimensional dynamic array to emulate a twodimensional

array and returns a pointer to the one-dimensional

dynamic array.

rows is the number of rows desired in the two-dimensional array.

columns is the number of columns desired in the two-dimensional array.

Return value: a pointer to a one-dimensional dynamic array large

enough to hold a two-dimensional array of size rows * columns.

Note that int ptr = create2DArray(2,3); would create an array analogous

to that created by int ptr[2][3];

void set(int *arr, int rows, int columns,

int desired_row, int desired_column, int val);

This stores val into the emulated two-dimensional array at position

desired_row, desired_column. The function should print an error message

and exit if the desired indices are invalid.

arr is the one-dimensional array used to emulate a two-dimensional array.

rows is the total number of rows in the two-dimensional array.

columns is the total number of columns in the two-dimensional array.

desired_row is the zero-based index of the row the caller would like

to access.

desired_column is the zero-based index of the column the caller

would like to access.

val is the value to store at desired_row and desired_column.

int get(int *arr, int rows, int columns,

int desired_row, int desired_column);

This returns the value in the emulated two-dimensional array at position

desired_row, desired_column. The function should print an error message

and exit if the desired indices are invalid.

arr is the one-dimensional array used to emulate a two-dimensional array.

rows is the total number of rows in the two-dimensional array.

columns is the total number of columns in the two-dimensional array.

desired_row is the zero-based index of the row the caller would like

to access.

desired_column is the zero-based index of the column the caller

would like to access.

Create a suitable test program that invokes all three functions.