Alocating memory depending of a variable value INT variable

[Carlos]

Well in C I just declared an array during execution with an array 
with a multiplied variable for the size of the array.

Since I only need two spaces in the array for each line of 
process it was multiplied by two.

so it was like this :

scanf("%d", &Num);
int array[Num*2];

When I tried to do this on D, well it says the variable cannot be 
read at compile time.

I don't know how the C language implements this but the main 
thing is that it does.

So how can I manage memory depending on the user's input in D ?


Thank you for your attention.