Im wondering if its possible in C programming language to declare a 2D matrix with the second index declared as variable. Without using argv[n] command line.
For example

#include <stdio.h>
#include <stdlib.h>

int main(int argc, char** argv){
  int a;
  scanf("%d", &a)

  int matrix[][a]

  SNIP...

I’m studying C for physics son i cannot try too many other things to try to resolve this.