Insert a Node at The end of the single link list program in C using switch |Studyinight Programmer

#include<stdio.h>
#include<stdlib.h>
void append();
void display();
struct node

{

    int data;

    struct node* next;

};

root=NULL;

void append()

{

    struct node * temp;

    temp=(struct node*)malloc(sizeof(struct node));

    printf("Enter node data\n");

    scanf("%d",&temp->data);

    temp->next=NULL;

    if(root==NULL)

        root=temp;

    else

    {

        struct node * p;

        p=root;

        while(p->next!=NULL)

        {

            p=p->next;

        }

        p->next=temp;

    }

}

void display()

{

  struct node * temp;

  temp=root;

  if(temp==NULL)

        printf("List is Empty\n");

  else

  {

      while(temp!=NULL)

      {

          printf("%d-->",temp->data);

          temp=temp->next;

      }

      printf("NULL\n");

  }

}

int main()

{

    int ch;

    while(1)

    {

        printf("1.Insert element at The End\n");

        printf("2.Display element\n");

        printf("3.exit\n");

        printf("Enter your choice\n");

        scanf("%d",&ch);

        switch(ch)

        {

        case 1:

            append();

            break;

        case 2:

            display();

            break;

        case 3:

            exit(1);

        default:

            printf("Please enter right choice\n");

        }

    }

}