When I type:
int n;
cin >> n;
int a[n];
It works on VS code but doesn't work on Visual Studio.
I expected it not to work at all because of memory-related stuff.
So, any explanation why it does work on VS code ?
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Editor doesn’t matter, it’s about the compiler. It’s not standard feature so there’s no requirement for it to work. Some compilers allow it – Sami Kuhmonen Feb 27 '21 at 06:36
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What does "works on VS code" mean? VS Code is an editor, not a compiler. – jamesdlin Feb 27 '21 at 06:36
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3Just don't do it. It's not standard C++. If you need runtime-sized arrays, use `std::vector`. – jkb Feb 27 '21 at 06:40
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@jamesdlin I checked compiler settings in both environment. It's identical! – mark coder Feb 27 '21 at 08:20
1 Answers
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a[n] is variable-length array (VLA) which is a C99 feature. It is not a C++ feature. Some C++ compilers, never the less, accept the syntax as a compiler extension.
Allan Wind
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1Does the memory allocated for the array in our case belongs to stack or heap? If heap, can a memory leak happens as expected? should I delete it ? – mark coder Feb 27 '21 at 08:19
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It depends on the compiler. gcc allocates it on the stack and why it's dangerous. You don't need to deallocate it. – Allan Wind Feb 27 '21 at 08:23