[Beginner]Variable length arrays

[helxi via Digitalmars-d-learn]

On Saturday, 25 February 2017 at 14:34:31 UTC, rikki cattermole 
wrote:
> On 26/02/2017 3:31 AM, helxi wrote:
>> I am trying to create an array which has a user defined size. 
>> However
>> the following program is not compiling:
>>
>> import std.stdio;
>>
>> void main(){
>>     write("Enter your array size: ");
>>     int n;
>>     readf(" %s", &n);
>>     int[n] arr; //<-Error: variable input cannot be read at 
>> compile time
>>     writeln(arr);
>> }
>>
>> 1. What's causing this?
>
> T[X] is a static array, its size must be known at compile time.
> Static arrays are passed around by value not by reference and 
> generally get stored on the stack not the heap.
>
>> 2. How can I get around this? I know I can always create a 
>> loop that
>> appends value 'n' times.
>
> This is where you want a dynamic array, allocated on the heap 
> at runtime.
>
> T[] array;
> array.length = n;

Thanks