linked_list.c~

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include "linked_list.h"


List *create_list() {
    List *new_list = malloc(sizeof(List));
    Node *first = create_node();
    new_list->first=first;
    return new_list;
}

Node *create_node() {
    Node *temp = malloc(sizeof(Node));
    temp->next=NULL;
    return temp;
}

void delete_list(List *list) {
    Node *node = list->first;
    Node *next;
    while(node) {
        next = node->next;
        delete_node(node);
        node=next;
    }
    free(list);
}

void remove_node(List *list, unsigned int pid) {
    Node *node = list->first;
    if(node->pid == pid) {
        list->first = node->next;
        free(node);
        return;
    }
    while(node != NULL) {
        if(node->next == NULL) break;
        if(node->next->pid == pid) {
            Node *temp = node->next;
            node->next=node->next->next;
            free(temp);
            return;
        }
        node = node->next;
    }
}
void delete_node(Node *node) {
    free(node);
}

void append_list(List *list, unsigned int pid, int priority) {
    Node *node = list->first;
    while(node->next != NULL) { node=node->next; }
    node->pid=pid;
    node->priority=priority;
    node->next=create_node();
}
/*
void insert(List *list, unsigned int pid, int priority) {

    //Set up node to insert
    Node *temp; Node *node;
    temp=create_node();
    temp->pid=pid;
    temp->priority = priority;

    Node *prev_node = malloc(sizeof(Node));

    //Node is either first in the list, or has a higher priority than the first item on the list.
    if(list->first == NULL || priority < list->first->priority) {
        temp->next=list->first;
        list->first = temp;
    } else {
    //Iterate through the nodes until you find one that has less priority, then put the Node in front of it. 
        node=list->first;
        while(node->next != NULL) {
            if(node->priority >= priority) {
               prev_node->next=temp;
               temp->next=node;
               goto done;
            }
            prev_node=node;
            node=node->next;
        }

        prev_node->next=temp;
        temp->next=node;
    }

    done:
        free(prev_node);
        return;
}

Node *pop(List *list) {
    Node *temp = list->first;
    if(temp->next == NULL) {
        Node *new_first = create_node();
        list->first=new_first;
    } else {
        Node *new_first=temp->next;
        list->first=new_first;
    }
    return temp;
}
*/
void insert(List *list, unsigned int pid, int priority) {
Node *temp; Node *node;
temp=create_node();
temp->pid=pid;
temp->priority = priority;
if(list->first == NULL || priority < list->first->priority) {
temp->next=list->first;
list->first = temp;
} else {
node=list->first;
Node *prev_node;
while(node->next != NULL) {
if(node->priority >= priority) {
prev_node->next=temp;
temp->next=node;
return;
}
prev_node=node;
node=node->next;
}
prev_node->next=temp;
temp->next=node;
}
}


Node *peek(List *list) { return list->first; }

Node *get_element(List *list, int element) {
    Node *node = list->first;
    int i = 0;
    while(i < element && node != NULL) { node=node->next; i++; }
    return node;
}

Node *find_pid(List *list, unsigned int pid) {
    Node *node = list->first;
    while(node->next != NULL) {
        if(node->pid == pid) { return node; }
        node=node->next;
    }
    return NULL;
}

int print_list(List *list) {
    Node *node = list->first;
    int i=0;
    while(node->next != NULL) {
        printf("Pid: %d\t Priority: %d\n",node->pid,node->priority);
        node = node->next;
        i++;
    }
    printf("\n");
    return i;
}

int main(int argc, char *argv[]) {
    List *list = create_list();
    int i;
    append_list(list,1,6);
    print_list(list);
    append_list(list,2,8);
    insert(list,3,4);
    insert(list,4,1);
    insert(list,5,5);
    insert(list,6,-2);
    insert(list,7,10);
    insert(list,8,-100);
    print_list(list);
    remove_node(list,8);
    printf("------------------------------------\n");
    print_list(list);
    remove_node(list,4);
    printf("------------------------------------\n");
    print_list(list);
    pop(list);
    print_list(list);
}