When should I use delete? (Consequences of not deleting after a dynamically created 2d array)
I am new to dynamic allocation and pointers. I will try to fill out a 2D dynamic array from a file and then apply a maze-solving algorithm (wall follower)on it.
Assuming I create a dynamically allocated 2D array like this:
int** board;
board = new int* [rowsize];
for(int row = 0; row < rowsize; row++)
{
board[row] = new int[colsize];
}
If I know that I won't be using this pointer for another variable, can I get away with not using delete for
boarddelete board
can I get away with not using delete for
board?
Yes, but not for very long: repeated failure to delete arrays that your program allocates is a memory leak that eventually runs your process out of memory.
how do I delete a pointer to a pointer, would
delete boardbe sufficient?
No, you will need to delete each pointer that you allocated and stored inside board:
for(int row = 0; row < rowsize; row++) {
delete[] board[row];
}
delete[] board;
Note square brackets after delete to indicate that you deleting an array, they are very important.
Allocating an deallocating memory for a rectangular matrix is a solved problem in C++ library. Switch to using a vector of vectors to avoid dynamic resource allocations:
std::vector<std::vector<int>> board(rowsize, std::vector<int>(colsize, 0));