Thread: Is this bad?

Code:

#include <stdio.h>

void change_x(int **x)
{
    *x = (int *)10;
}

int main(void)
{
    int *x = NULL;
    
    change_x(&x);
    
    printf("%d\n", x);
    
    return 0;
}

I'll be using a linked list in my next stupid program and I don't want to use any global variables. This was my practice
Is this correct? gcc didn' t give me any errors or warnings. Thanks.

Code:

printf("%d\n", x);

^---- bad

That code is bad in general. You have x declared as a pointer to an integer, and it's pointer value is modified by the function change_x. A logical assumption would be that the programmer could then dereference the value of x, but in this case it would crash the program. Why not keep it simple and just do:

Code:

#include <stdio.h>

void change_x(int *x)
{
    *x = 10;
}

int main(void)
{
    int x = 0;
    
    change_x(&x);
    
    printf("%d\n", x);
    
    return 0;
}

I'm not sure what your code has to do with a linked list, so maybe I'm missing the point of this little exercise.

I want to write an add_node function that will not depend on a global variable head.

I want to write an add_node function that will not depend on a global variable head.

Well, head need not be global, you can always pass head to your add_node function.

Sahil

I guess I understand your problem

Code:

void add_node(node **head ){
    node * newnode = malloc(sizeof( node ) );
    if ( *head == 0 ) {
          *head = newnode;
    }
    else 
       .....
}

int main() {
   node * head;
   head = 0;
   add_node( &head );  // head will be initialized in add_node
   return 0;
}

And yes that would work.

Kurt