How to create an array with number of elements from a variable?

Question

I have an integer num that was read from a file. I want to create an array with the number of elements being num.

A sample code of what I want to do but doesn't work:

int num;
cin >> num;
int iarray[num];

`std::vector ar(num);`, assuming of course you checked the return value of that read op *and* ensured `num` is a reasonable value (i.e. not negative, etc). — WhozCraig, Feb 17 '13 at 00:39

score 5 · Accepted Answer · answered Feb 17 '13 at 00:45

5

Arrays in C++ have compile-time bounds.

Use dynamic allocation instead, or a healthy std::vector wrapper around the same process.

answered Feb 17 '13 at 00:45

score 1 · Answer 2 · answered Feb 17 '13 at 00:59

1

dynamic allocation being int * iarray = new int[num];

Just make sure to call delete[] iarray; at some point to free the memory.

answered Feb 17 '13 at 00:59

thisisdog

2 Answers2