A basic singly Linked List with addAtEnd(), addAtBeg(), display() and more operations.

BasicLL.c

#include <stdio.h>
#include <stdlib.h>

struct node{
    int val;
    struct node *next;
};

int addAtEnd(struct node **h, int x){
    
    if(*h == NULL){     //If the list is empty, add at the head and return.
        *h = (struct node*)malloc(sizeof(struct node));
        (*h)->val = x;
        (*h)->next = NULL;
        return 0;
    }
    
    struct node *temp = *h;
    while (temp->next!=NULL) {      //Traverse to the end of the list.
        temp = temp->next;
    }
    
    temp->next = (struct node*)malloc(sizeof(struct node));     //Create a node at ptr->next, which is NULL.
    temp->next->val = x;
    temp->next->next = NULL;
    return 0;
}

int addAtBeg(struct node **h, int x){
    
    if(*h == NULL){     //If the list is empty, add at the head and return.
        *h = (struct node*)malloc(sizeof(struct node));
        (*h)->val = x;
        (*h)->next =NULL;
        return 0;
    }
    
    struct node *ptr, *temp = *h;
    ptr = (struct node*)malloc(sizeof(struct node));        //Create a node and then point the head to it.
    ptr->val = x;
    ptr->next = NULL;
    
    *h = ptr;
    (*h)->next = temp;
    
    return 0;
}

int addAtBegArray(struct node **h, int array[], int size){
    
    int i;
    for (i=size-1; i>=0; i--) {

        addAtBeg(h,array[i]);
    }
    return 0;
}

int addAtEndArray(struct node **h, int array[], int size){
    
    int i;
    for (i=0; i<size; i++) {
        
        addAtEnd(h,array[i]);
    }
    return 0;
}

void display(struct node *h){
    if (h == NULL) {
        printf("Empty");
    }
    while (h!=NULL) {       //Traverse and print the value till the current node is not NULL.
        printf("%d ",h->val);
        h = h->next;
    }
    printf("\n");
}

int getSize(struct node *h){
    
    int count = 0;
    if (h == NULL) {
        return -1;
    }
    while (h!=NULL) {       //Traverse and get count.
        h = h->next;
        count++;
    }
    return count;
}

int getKthVal(struct node *h, int k){
    
    int count = 0, val;
    
    while (h!=NULL) {       //Traverse and get count.
        count++;
        if (count == k) {
            return h->val;
        }
        h = h->next;
    }
    return -1;
}

struct node *concatList(struct node **l1, struct node **l2){
    
    struct node *temp;
    temp = *l1;
    if(*l1 == NULL)
    {
        return *l2;
    }
    
    while (temp->next!=NULL) {
        temp = temp->next;
    }
    temp->next = *l2;
    
    return *l1;
}

struct node *copyList(struct node *l1){
    
    struct node *temp=NULL;
    while (l1!=NULL) {
        addAtEnd(&temp,l1->val);
        l1=l1->next;
    }
    return temp;

}
void partitionArnd(struct node **h, int x){
    
    struct node *ll_gt = NULL, *ll_lt = NULL;
    struct node *temp, *temp_b;
    
    temp = *h;
    while (temp!=NULL) {
        if (x <= temp->val) {
            addAtEnd(&ll_gt, temp->val);
        }else{
            addAtEnd(&ll_lt, temp->val);
        }
        temp_b = temp;
        temp = temp->next;
    }
    //display(ll_lt);
    //display(ll_gt);
    while ((*h)!=NULL) {        //free old list
        temp=(*h);
        (*h) = (*h)->next;
        free(temp);
    }

    *h = concatList(&ll_lt, &ll_gt);
}

void sort(struct node **h){
   
    struct node *head_copy = NULL;
    int i;
    head_copy = copyList(*h);
    for (i=0; i<getSize(head_copy); i++) {          //sorting O(n2)
        partitionArnd(h,getKthVal(head_copy, i+1));
        //display(*h);
    }
}

int delKthVal(){
    
}

int main(){
    
    struct node *head = NULL;       //set as NULL or else it may break while adding
    
    int array[]={5,7,90,-7};
    addAtBeg(&head,2);
    addAtEnd(&head,0);
    addAtEnd(&head,-5);
    addAtEnd(&head,9);
    addAtBeg(&head,4);
    addAtBeg(&head,1);
    display(head);
    addAtBegArray(&head,array,sizeof(array)/sizeof(int));
    display(head);
    sort(&head);
     
    display(head);
    return 0;
}

output.txt

1 4 2 0 -5 9 
5 7 90 -7 1 4 2 0 -5 9 
-7 -5 0 1 2 4 5 7 9 90