Program For Stack using Linked List

class Nodetype
{
int info;
Nodetype next;


Nodetype(int i)
{
info=i;
next=null;
}
}
//--------------------------------------------------------------------------------------------------------------
class Operations
{
Nodetype top=null;


/*Where top is the pointer which will point to the element
at the top of the stack hence it will act as the external
pointer list.*/
void display( )
{
/*display all elements of linked list*/


Nodetype temp;
if(top==null)
System.out.println("\nEmpty linked list");
else
{
System.out.print("Stack\n");
temp=top;
while(temp!=null)
{
System.out.println("     "+temp.info);
temp=temp.next;
}
}
}
void push(int x)
{
Nodetype node=new Nodetype(x);
node.info=x;
node.next=top;
top=node;
display();
}/*end push*/
//--------------------------------------------------------------------------------------------------------------
void pop()
{
Nodetype p=null;
int x;
p=top;
if(p==null)
{
System.out.println("\nStack Underflow\n");
return;
}
System.out.print("\n\nThe element popped is "+p.info+"\n");
top=top.next;
//display();
}/*end pop*/
//--------------------------------------------------------------------------------------------------------------
void stacktop()
{
if(top==null)
{
System.out.println("\nStack is empty\n");
return;
}
System.out.println("\nThe element at the top of the stack is "+top.info+"\n");
display();
}/*end stacktop*/
}
//--------------------------------------------------------------------------------------------------------------
class LLStack
{
public static void main(String args[])
{
Operations L =new operations();
int i,j;
for(i=0;i<5;i++)
{
j = new Integer((int)(Math.random() * 100));
System.out.println("\n\nPush: " + j);
L.push(j);
}
//L.display();
for(i=0;i<3;i++)
{
L.pop();
L.stacktop();
}
for(i=0;i<2;i++)
{
j = new Integer((int)(Math.random() * 100));
System.out.println("\n\nPush: " + j);
L.push(j);
}
}/*end main*/
}


/*
Sample Input and Output :
Push: 19
Stack
     19


Push: 66
Stack
     66
     19
Push: 3
Stack
     3
     66
     19


Push: 80
Stack
     80
     3
     66
     19


Push: 80
Stack
     80
     80
     3
     66
     19


The element popped is 80


The element at the top of the stack is 80


Stack
     80
     3
     66
     19


The element popped is 80


The element at the top of the stack is 3


Stack
     3
     66
     19


The element popped is 3


The element at the top of the stack is 66


Stack
     66
     19


Push: 83
Stack
     83
     66
     19


Push: 43
Stack
     43
     83
     66
     19
*/