can size of array be determined at run time in c?

Question

As I know, an array needs to have a specific size before compiling time in c.

I wonder why this code still works?

int s;
printf(\"enter the array si         


        

Answer 1

Its important to understand how memory is allocated to variable by a compiler to give proper answer to your question. There are two modes in which memory is allocated to variable, it can be on a heap or it can be on a stack. Memory on a heap is allocated dynamically. So a variable that is allocated memory on a heap can be given its size during run time.

The arrays in case of C are given memory on a stack. For providing memory on a stack the size of the memory should be known to the compiler during compile time. So that during run time that much memory can be set aside for the variable on the stack. That is the reason you cannot decide the size of the array at run time as far as C language is concerned.