can we give the number of elements in an array as needed without using a variable?

#include <stdio.h>

int main() {
    int n;
    scanf("%d", &n);
    int L[n];
    // ...
    return 0;
}

I’m asking if I can give the number of elements in an array as needed using a variable . The teacher told us that this method is not recommended and I did not understand why. Thanks for answering for my question .

>Solution :

This declaration

int L[n];

is a declaration of a variable length array. Variable length arrays are conditionally supported by compilers.

So it is not excluded that you can meet a compiler that does not support such declarations.

Pay attention to that in this declaration the value of the variable n shall be greater than 0.

As such an array has automatic storage duration then its size should not be vary big. Otherwise you should allocate memory for the array dynamically.