How to do it in Ada ?

[taw@pb220.legnica.sdi.tpnet.pl (Tomasz Wegrzanowski)]

int main(int argc, char **argv)
{
    int *x;
    int n;
    
    n = (argc==1)?1:atoi(argv[1]);
    x = malloc (n*sizeof(int));
    for (x=0;x<n;x++)
	x[i]=0;
    
    /* ... */
}

Something like that ... how to do such dynamic array allocation in Ada ?