Create a big array in C++ [duplicate]

Answer 1

Use dynamic allocation or the STL. There was a recent thread about a very similar question. See this.

Answer 2

If you want to avoid new[], or avoid using std::vector, make the array global. This will put the array on heap and stack overflow will not occur.

Answer 3

Your declaration looks a bit as if dp will be used as a matrix. In that case, a dedicated (dense) matrix class such as boost::numeric::ublas::matrix is the simplest solution, easier and more local than a vector of vectors. If the matrix is sparsely populated, use a sparse matrix class instead.

Answer 4

Your stack has overflowed with too many bits. You must drain them. Preferably onto a heap of other bits. I suggest /F67108864. The /F stands for "F'ing hell why is the stack so small compared to the heap?". The 67108863 is arbitrary.

Answer 5

So if I want to create a big array like above, what should I do?

Avoid using the stack for these cases (in other words, avoid creating arrays like these which aren't heap-allocated when working inside a function). Just to give you an idea, my thread-local stack is only 16 kilobytes large. 4501 * 4501 * 4 (assuming 4 bytes per int) = ~81 megabytes.

Consider something like this instead:

typedef vector<int> Row;
typedef vector<Row> Matrix;
Matrix dp(4501, Row(4501) );

If you want to create a 10x50 matrix:

Matrix dp(10, Row(50) );

You can use this just like your normal dp array had it not overflowed the stack. This one will be allocated and automatically deallocated to/from the heap so that you don't have to worry about stack overflow when using it.

dp[5][10] = 123;

Good luck!

[Edit] There are also matrix solutions in boost worth looking into but suggesting boost might be a bit premature given the nature of the topic.

Answer 6

Put it on the heap.