list.c

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

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

void insert(struct Node* head, int value);
void print(struct Node *head);

int main(){
    struct Node *head;

    head = (struct Node*)malloc(sizeof(struct Node));

    int i = 0;

    for(i = 0; i<10; i++)
        insert(head, i*2);

    print(head);

    return 0;
}

void insert(struct Node* head, int value){
    if(head == NULL){
        printf("NULL");
        head->val = value;
        head->next = NULL;
    }
    else {
        printf("nULL2\n");
    struct Node *tmp = (struct Node*)malloc(sizeof(struct Node));
    tmp->val = value;
    tmp->next = NULL;

    while(head->next != NULL){
        head = head->next;
    }

    head->next = tmp;
    }
}

void print(struct Node *head){
    struct Node *current = head;
    while(current != NULL){
        printf("%d\n", current->val);
        current = current->next;
    }
}