Thread: Stupid Q regarding array

Standard C++ does not support variable length arrays. Use std::vector<int> instead.

That's probably because std::vector would be your default choice for storing variable amounts of stuff in.

Note, however, that if you used the const keyword you could declare your array as well. (But only if you are dealing with real constants whose value is known to the compiler. You can't for example get input at runtime and then create an array of that size, even if you store the entered value in a const variable.)

Code:

int main()
{
    const int x=2;
    const int y=3;
    const int z=x*y;
    int someArray[z];
}

Originally Posted by Cathalo

I get you Anon.So once the compiler sees that any of the variables can change and as a result the someArray could be of any size it throws up the errors.

Normally I always knew what size the array should be so always declared haow many elements it had.

I ended up trying the code I posted because I thought it was waste of memory and what have you setting up an array with 800 elements and only using the 1st 40 or so elements.

And so thats what vectors are for

Thanks for the replys and explanations

You're right. It would be wastage of memory if only a few elements are used. That's why dynamic allocation of memory is used and in C++ as you said vectors are used for the same purpose.