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Asked: 2026-05-24T01:59:02+00:00

int d; cin >> d; int asdf[d]; Is this considered dynamic memory allocation? According

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int d;
cin >> d;
int asdf[d];

Is this considered dynamic memory allocation? According to http://www.cplusplus.com/doc/tutorial/dynamic/, it seems like I shouldn’t even be able to compile this, because arrays without using the new operator can only be declared with constant size, maybe I read it wrong. (I’m using CodeBlocks with GNU CCC compiler)

What is the difference between that and

int d;
int *asdf;
cin >> d;
asdf = new int[d];

Is the only difference that array created using new lives until it is deleted, whereas the first array becomes freed as soon as you leave the scope?

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1 Answer

  1. Editorial Team

    int x[n]; is a variable-length array (VLA), which has automatic storage duration (i.e. “on the stack”). It is not valid in C89 or C++98/03, but it was introduced in C99 and is commonly available as an extension, e.g. in GCC.

    The functionality can also be mimicked on some platforms with the non-standard alloca() function, which was used before VLAs became common.

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