Thread: A question about pointers in functions

I'm programming (in Ansi C) an adjacency list of an array with each element pointing to a list of structs and compiling with

gcc -Wall -ansi -pedantic -O *.c

my question is simply that from within main I can easily move down and print out all of these lists BUT...

if I try to do this with a function I can't seem to get it to print more than the first list at array[o].

for example in main this prints all lists

Code:

k = 0;
	
	while(k < n_vertices)
	{
	    printf("\n\n");
		printf("List: %d\n", k);
		print(*g++);
		k++;
	}

while in my file nodes.c in the same directory this call from main

Code:

print_all_lists(*g, n_vertices); /* n_vertices is the sizeof the array; */

means I can't seem to get the iterative call to print working...

Code:

void print_all_lists(node_ptr arr, int arr_length)
{
	int k = 0;
	
	while(k < arr_length)
	{
	    printf("\n\n");
		printf("List: %d\n", k);
		
		print(arr);

		k++;
	}
}

Obviously print(arr) in nodes.c is going to repeatedly print the first list but every way I've tried to increment down (like I did in main) just makes the program crash.

Could anyone offer any advice into what I am missing in my understanding. Why could I do this in main but can't seem to do so from other files?

Hi Zacs7, yes it is already a pointer to a linked list...

what I'm saying is from main() the code using 'g' will print out the entire set of lists iterating down the array of pointers...

but when I try from a function on another file I can't get it to print out all of the lists in the same way by passing a 'print(*arr++)' call for example.

I'll hunt up the reason today but have just become very curious as to why exaclty I could pass that *g++ from main but can't achieve the same result from a function on the same file as print(node_ptr the_list).

Thanks for the reply though, feedback is appreciated.