Delete first node of a singly linked list

Below is the code to delete first node of a singly linked list

#include <stdio.h>
#include <stdlib.h>
struct node{
    int data;
    struct node *next;
};
struct node *head;
void create_linked_list(int element){
    struct node *temp=malloc(sizeof(struct node));
    temp->data=element;
    temp->next=NULL;
    if(head==NULL){
        head=temp;
    }
    else{
        struct node *ptr=head;
        while(ptr->next!=NULL){
            ptr=ptr->next;
        }
        ptr->next=temp;
    }
}
void del_first(){
    if(head==NULL){
        printf("List is already empty");
    }else{
        struct node *temp=head;
        head=head->next;
        free(temp);
    }
}
int main(){
    create_linked_list(30);
    create_linked_list(20);
    create_linked_list(10);
    create_linked_list(18);
    del_first();
    //traversing the linked list
    struct node *ptr=head;
    while(ptr!=NULL){
        printf("%d\t",ptr->data);
        ptr=ptr->next;
    }
}

OUTPUT:

20 10 18