Insertion at end in Circular Linked List in C++

#include <iostream>
using namespace std;

struct node {
    int num;
    struct node * next;
}*head;

void make(int n)//function to build linked list
{
    int i, num;
    struct node *preptr, *newnode;

    if(n >= 1)
    {
        head = (struct node *)malloc(sizeof(struct node));

        cout<<"Enter data of the list:\n"; cin>>num;
        head->num = num;
        head->next = NULL;
        preptr = head;
        for(i=2; i<=n; i++) { newnode = (struct node *)malloc(sizeof(struct node)); cin>>num;
            newnode->num = num;
            newnode->next = NULL;	
            preptr->next = newnode;	
            preptr = newnode;   		
        }
        preptr->next = head; 		//linking last node with head node
    }
}

void insertEnd(int num1)//function to insert element at end 
{
        struct node *p;
		int a;
		a=num1;
		struct node *temp=(struct node*)malloc(sizeof(struct node));
		temp->num=a;
		p=head;
		while(p->next!=head)
		{
			p=p->next;
		}
		p->next=temp;
		temp->next=head;
}
void display()//function to display list
{
    struct node *tmp;
    int n = 1;
    
    if(head == NULL)
    {
        cout<<"List is empty";
    }
    else
    {
        tmp = head;
        
        cout<<"\nCircular linked list data:\n";
        do {
            cout<<tmp->num<<" "; tmp = tmp->next;
            n++;
        }while(tmp != head);
    }
}
int main()//main function
{
    int n,num1;
    head = NULL;
    cout<<"Enter the size of circular linked list: "; cin>>n;
    make(n); 
    display();
	cout<<"\nEnter data to be inserted at end: "; cin>>num1;
    cout<<"\nAfter insertion data at end list is:";  
    insertEnd(num1);
    display();	
    return 0;
}