How to create a 2D array using a function? - c++

Question

I am trying to define a 2D array, but I want to do it in a function,
here is my code:
int** createArray( int columns, int rows)
{
int** array[rows];
for(int i = 0; i < rows; i++)
{
array[i] = new int*[columns];
}
for(int i = 0; i <columns; i++)
{
for(int j = 0; j < rows; j++)
{
array[i][j] = 0;
std::cout <<array[i][j];
}
std::cout<<"\n";
}
return *array;
}
int main()
{
int **myArray = createArray(3,5);
for(int k =0; k < 5; k++)
{
if( (myArray[0][k] == 0) && (&myArray[1][k] == 0)) //segmentation fault
{
myArray[2][k] = 10; //segmentation fault
}
delete[] myArray;
}
But it causes errors which can be seen as comments in lines. I am new to C++ and I do not know how to fix this.
Thank you very much

Answer 1

Prefer std::vector over manual memory management:
std::vector<std::vector<int>> createArray(int columns, int rows)
{
return std::vector<std::vector<int>(rows, std::vector<int>(columns));
}
int main()
{
int COLUMNS = 5;
int ROWS = 3;
auto myArray= createArray(COLUMNS, ROWS);
/*
Do stuff
*/
//std::vector handles delete on it's own, no need to clean up
}
If you cannot use std::vector for some reason, this is the a way to initialize 2D array on the heap:
int** createArray(int columns, int rows)
{
int** arr = new int*[rows];
for(int i = 0; i < rows; ++i)
{
arr[i] = new int[columns];
}
return arr;
}
int main()
{
int COLUMNS = 5;
int ROWS = 3;
int** myArray= createArray(COLUMNS, ROWS);
/*
Do stuff
*/
//you need to a delete for every new and delete[] for every new[]
for(int i = 0; i < rows; ++i)
{
delete[] myArray[i];
}
delete[] myArray;
}