circular link list insertion at beginning

Question

I am doing the insertion at the beginning but my code inserts it in the end. I am thinking about that but I think my logic is right. I think that first I make a pointer p and initialized it as head then increment it till it is not equal to head and then make a new link. Is it a right approach?

Here it is,

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

typedef struct node{

    int data;
    struct  node *next;
        
}sll;

void traversal(sll* head){

    sll* p;
    p=head;
       
    do
    {
        printf("%d\n",p->data);
        p=p->next;
    }while (p!=head);
    
}

sll* insertionstart(sll* head,int data){

        sll* ptr=(sll*)malloc(sizeof(sll));
        ptr->data=data;
       
        sll* p=head;
         do
        {
           p= p->next;
    }   while (p->next!=head);
        
         p->next=ptr;
        ptr->next=head;
        
        return head;
        
        
}

int main(){
    sll* ptr;
    sll* head;
    sll* second;
    sll* third;
    sll* fourth;
    sll* fifth;

    

    head = (sll*) malloc(sizeof(sll));
    second = (sll*) malloc(sizeof(sll));
    third = (sll*) malloc(sizeof(sll));
    fourth = (sll*) malloc(sizeof(sll));
    fifth = (sll*) malloc(sizeof(sll));


    head -> data=56;
    head ->next=second;

    
    second -> data=3;
    second->next=third;

    
    third -> data=18;
    third ->next=fourth;

    
    fourth -> data=90;
    fourth ->next=fifth;

    fifth -> data=76;
    fifth ->next=head;

    traversal(head);
    printf("*******************\n");
    head=insertionstart(head,42);
    traversal(head);

    return 0;
}

Answer 1

If you want the new element to be the new head, then simply make this change in insertionstart:

return head;  -->  return ptr;