Untitled

#include<stdio.h>
#include<stdlib.h>
struct node
 {
 int data;
 struct node*next;
 }*top=NULL;
 void push()
 {
   struct node*newnode=(struct node*)malloc(sizeof(struct node));
   printf("/n enter the data to be inserted");
   scanf("%d",&newnode->data);
   if(top==NULL)
   newnode->next=NULL;
   else
   newnode->next=top;
   top=newnode;
   }
   void pop()
   {
    if(top==NULL)
    printf("\n empty stack");
    else
    {
     struct node*temp=top;
     printf("/n deleted element %d",temp->data);
     top=temp->next;
     free(temp);
     }
    }
    void display()
    {
     if(top==NULL)
     printf("\n empty stack");
     else
     {
     struct node*temp=top;
     printf("\n the stack is");
     while(temp!=NULL)
      {
	printf("%d->",temp->data);
	temp=temp->next;
      }
      printf("null");
      }
    }
    void main()
  {
   int ch,value;
   while(1)
   {
   printf("\n....menu....\n");
   printf("\n1.insert\n2.delete\n3.display\n4.exit");
   printf("\n enter choice");
   scanf("%d",&ch);
    switch(ch)
   {
   case 1:
   printf("\n value to be inserted is");
   scanf("%d",&value);
   push(value);
   break;
   case 2:
   pop();
   break;
   case 3:
   display();
   break;
   case 4:
   exit(0);
   break;
   default:
   printf("\n wrong choice");
   }
   }
   }