Linked List implementation of Queue

I am trying to create a queue using LL implementation that will be used for Radix Sort.

The algorithm of the radix sort is described as follows:
(a) Read in the numbers from a file and create a queue called
Master.
(b) Create 10 other queues called Subqueue[0], Subqueue
[1],. . . ,Subqueue[9].
(c) Remove a number from the Master queue and extract its most
right digit (ones).
(d) Add the number to the Subqueue[digit]
(e) Repeat the (c) and (d) until Master queue is empty.
(f) Remove the first element from the Subqueue[0] and insert it
into the Master queue.
(g) Repeat the previous step until the Subqueue[0] is empty.
(h) Repeat the last step for consecutive Subqueue[i] where i
takes on values from 2 to 9.
(i) Repeat the procedure starting from (b) Max times where the
value of Max is equal to the number of digits
in the largest number of the sequence.

I don't know how to start (newbie). Can someone please help.

Start by creating a few functions to allow you to insert and remove items (in this case ints).

Code:

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typedef struct _ll_node {
    int data;
    struct _ll_node *next;
} ll_node;

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So then you can declare
ll_node *master;
ll_node *subqueue[10];

And perhaps a function with this prototype
ll_node *add_to_list ( ll_node *head, int data );

And you would perhaps call it like
master = add_to_list( master, my_data );

Quote:

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Originally posted by Salem


....
....

And perhaps a function with this prototype
ll_node *add_to_list ( ll_node *head, int data );

And you would perhaps call it like
master = add_to_list( master, my_data );


Can we return the new value of master without using a return statement?? I mean return it by reference to an argument???

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> Can we return the new value of master without using a return statement?
Yes, like so

And perhaps a function with this prototype
void add_to_list ( ll_node **head, int data );

And you would perhaps call it like
add_to_list( &master, my_data );

Quote:

---

Originally posted by Salem
> Can we return the new value of master without using a return statement?
Yes, like so

And perhaps a function with this prototype
void add_to_list ( ll_node **head, int data );

And you would perhaps call it like
add_to_list( &master, my_data );

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Can you tell me which is the preferred way? Which one is used more often... The return statement or by reference to an argument?
The ** confuses me..
head point to the pointer who's value we want to change????
The pointer we want is *head???

> Can you tell me which is the preferred way?
Both are valid, and both are useful.

> Which one is used more often... The return statement or by reference to an argument?
I'd go for the return, but that's just me.

> The pointer we want is *head???
Thats it, you would say

Code:

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ll_node *new_node = malloc( sizeof( ll_node ) );
// some code which decides new_node should be the head
*head = new_node;

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It's all about counting & and *'s - an & (indirection) in the caller function has to be balanced by a *(dereference) in the called function, in order to update the caller's variable.