How To Change Multidimensional Array Size In Program? - c++

Question

Hey I was wondering how I could have settings in-game which would allow the user to set the size of the 'game-board' by changing the array values. Here is the code. I know the code is messy and over the place but it is my first program.
#include "stdafx.h"
#include "iostream"
#include "string"
#include "cstdlib"
#include "ctime"
int xRan;
int choicei = 17;
int choicej = 17;
const int row = 15;
const int col = 16;
int play = 0;
void fill(char Array[row][col]);
int main()
{
int play = 0;
char Array[row][col];
srand((unsigned int)time(0));
xRan = rand() % 15 + 1;
if (play == 0)
{
std::cout << "1. To Play Treasure Hunt!" << std::endl;
std::cout << "2. How To Play Treaure Hunt!" << std::endl;
std::cout << "3. Treaure Hunt Settings! (Comming Soon)\n" << std::endl;
std::cin >> play;
std::cout << "-----------------------------------------------------------------------" << std::endl;
}
if (play == 2)
{
std::cout << "1. Select a row number. Be sure to make it less than or equal to " << row << "!" << std::endl;
std::cout << "2. Select a column number. Be sure to make it less than or equal to " << col << "!" << std::endl;
std::cout << "3. If you see the 'X' you have won! If you see the 'O' you lose!" << std::endl;
std::cout << "-----------------------------------------------------------------------\n" << std::endl;
std::cin >> play;
}
if (play == 3)
{
std::cout << "\nComming Soon!" << std::endl;
std::cout << "-----------------------------------------------------------------------\n" << std::endl;
std::cin >> play;
}
while (choicei > row || choicej > col || choicei < 1 || choicej < 1)
{
std::cout << "\nEnter The Row Number Less Than Or Equal To " << row << "!" << std::endl;
std::cin >> choicei;
std::cout << std::endl;
std::cout << "Enter The Column Number Less Than Or Equal To " << col << "!" << std::endl;
std::cin >> choicej;
std::cout << "\n-----------------------------------------------------------------------" << std::endl;
if (choicei > row || choicej > row)
{
std::cout << "Make Sure The Row And Column Numbers Are Less Than Or Equal To " << row << "and" << col << "!\n" "---------------------------------------------------------------------- - " << std::endl;
}
if (choicei < 1 || choicej < 1)
{
std::cout << "Make Sure The Row And Column Numbers Are More Than Or Equal To 1" << "!\n" "-----------------------------------------------------------------------" << std::endl;
}
}
fill(Array);
std::cout << std::endl;
for (int i = 0; i < row; i++)
{
for (int j = 0; j < col; j++)
{
std::cout << Array[i][j] << " ";
}
std::cout << std::endl;
}
if (xRan > 11)
{
std::cout << "\nCongratulations! You Won!\n" << std::endl;
}
else
{
std::cout << "\nBetter Luck Next Time!\n" << std::endl;
}
}
void fill(char Array[row][col])
{
for (int i = 0; i < row; i++)
{
for (int j = 0; j < col; j++)
{
Array[i][j] = '*';
}
}
if (xRan > 11)
{
for (int i = 0; i < 1; i++)
{
for (int j = 0; j < col; j++)
{
Array[choicei - 1][choicej - 1] = 'X';
}
}
}
else
{
for (int i = 0; i < 1; i++)
{
for (int j = 0; j < col; j++)
{
Array[choicei - 1][choicej - 1] = 'O';
}
}
}
}
Thank you in advance.

Answer 1

you can't do that with ordinary arrays. you should use dynamic arrays, for example std::vector http://www.cplusplus.com/reference/vector/vector/

Answer 2

Actually, what you want to do can be done in C, not in C++: C++ requires array dimensions to be compile time constants, C can use any runtime value.
If you stay in C++, you should take a look at vector<>. If, however, you choose to use C you can simply remove the const from the declaration of row and col.

Answer 3

You may find this answer useful. It lists several methods to create dynamic arrays.
Quoting the answer :
In C++, variable length arrays are not legal. G++ allows this as an "extension" (because C allows it), so in G++ (without being -pedantic about following the C++ standard)
Based on the suggestions, here are some ways you could initialize it (ignoring how you take the input value) :-
vector<vector<char>> Array(row, vector<char>(col));
or
char **Array = new char*[row];
for(int i = 0; i < row; i++)
{
Array[i] = new char[col];
}
UPDATE
Based on the comments, I am adding how to use the vector method and use it with the function 'fill'. fill uses reference while fill_with_ptr makes use of pointer. Although I list both the methods, I strongly recommend the one using reference.
void fill(vector<vector<char> >& array);
void fill_with_ptr(vector<vector<char> >* array);
int main()
{
...
cin >> row;
cin >> col;
vector<vector<char> > Array(row, vector<char>(col));
...
fill (Array); // or fill_with_ptr(&Array);
}
void fill(vector<vector<char> >& array)
{
... // access elements as array[i][j]
}
void fill_with_ptr(vector<vector<char> >* array)
{
... // access elements as (*array)[i][j]
}