linked list adding an element

#include <stdio.h>
#include "stdlib.h"
typedef struct st{
    int data;
    struct st *next;
}node;

node* new_node(){
    return (node *) malloc(sizeof(node));
}

void add(int num, int ch, node **head, node **start){
    node* temp = new_node();
    temp->data = num;
    // At the end
    if(!ch){
        temp->next = NULL;
        temp->data = num;
        // printf("%d ", temp->data);
        (*head)->next = temp;
        //printf("%d \n", (*head)->next);
        *head = temp;
        //printf("%d \n", *head);
        return;
    }
    //Front
    temp->next = *start;
    *start = temp;
}
void display(node *head){
        if(head == NULL)
            return;
        if(head->data != -1)
        printf("%d ", head->data);
        display(head->next);
}
// Only deletes from Front
void delete_node(node **start){
   node* temp = *start;
    *start = temp->next;
}
int main(){
    node *head = new_node(), *start, *temp;// = new_node();Still works
    head->next = NULL;
    head->data = -1;
    start = head;
   // printf("%d\n", start->data);
    int n, num, ch;
    scanf("%d", &n);

    while(n--){
        scanf("%d %d", &ch, &num);
        //scanf("%d", &num);
        add(num, ch, &head, &start);
       // display(temp = start);
        printf("\n");
    }
    delete_node(&start);
        display(temp = start);
   // printf("%d", head->next);
   /* head = start;
    while(head != NULL){
        if(head->data != -1)
        printf("%d ", head->data);
        head = head->next;
       // display(start , head);
    }*/
  return 0;
}