Doubly link list with header circular

Doubly_link_list.cpp

#include<iostream>
#include<stdlib.h>
#include<conio.h>
using namespace std;
struct node {
    int data;
    struct node* next;
    struct node* per;
};

    struct node* Start_;
    struct node* End_;

struct node *temp, *head, *ptr;
void insert_in_list();
void disp_list();

int main() {
    head = (struct node*) malloc(sizeof(struct node));

    Start_ = head;
    End_ = head;
    head->per = End_;
    head->next= Start_;
    head->data = 0;

    int sel=1;
    while(sel) {
        cout<<"------------ Select Choice --------------";
        cout<<"\n1. Insert\n";
        cout<<"2. Display\n";
        int a;
        cout<<"Select :";
        cin>>a;
        switch(a) {
            case 1 : insert_in_list();
                     break;
            case 2 : disp_list();
                     break;
        }
    cout<<"1 To Count. 0 To exit : ";
    cin>>sel;
    }
}

void insert_in_list() {
    temp = (struct node*) malloc(sizeof(struct node));
    int counter;
    counter = head->data;
    cout<<"Node Value :";
    int X=0;
    cin>>X;
    temp->per = head;
    temp->data = X;
    temp->next = head->next;
    head->next = temp;
    counter++;
    head->data = counter;
    ptr = head;
    temp = head; // Calculation Previous Nodes
    while(ptr->next != Start_) {
    ptr=ptr->next;
    ptr->per=temp;
    temp=temp->next;
    }
    //ptr->per=temp;
    End_ = ptr;
    cout<<"\n\n Inserted \n\n";
}

void disp_list() {
    ptr = Start_->next;
    cout<<"\nStart :"<<Start_;
    cout<<"\nTail  :"<<End_<<"\n";

    while(ptr != Start_) {
        cout<<"\n------ \\ \\ \\ \\ "<<ptr<<" \\ \\ \\ \\ ------\n";
        cout<<"\t"<<ptr->per<<"\t"<<ptr->data<<"\t"<<ptr->next<<"\n";
        ptr=ptr->next;
        cout<<"|---------------------------------------|>\n";
    }
    getch();
}