Program for Queue using Linked List

class Nodetype
{
int info;
Nodetype next;
Nodetype(int i)
{
info=i;
next=null;
}
}
class Operations
{
Nodetype front=null,rear=null;
/*Where front is the pointer which will point to the front of the queue
and rear will point to rear end of the queue*/
void display()
{
/*display all elements of linked list*/


Nodetype temp;
if(front==null)
System.out.println("\nEmpty linked list");
else
{
System.out.print("\nfront");
temp=front;
while(temp!=null)
{
System.out.print("-->"+temp.info);
temp=temp.next;
}
System.out.println("<--rear");
}
} /* end display */
//--------------------------------------------------------------------------------------------------------------
void insert(int x)
{
Nodetype node=new Nodetype(x);
node.info=x;
node.next=null;
if (front==null&&rear==null)
{
front=node;
rear=node;
}
else
{
rear.next=node;
rear=node;
}
display();
}/*end insert*/
//--------------------------------------------------------------------------------------------------------------
void remove()
{
Nodetype p=null;
int x;
p=front;
if(p==null)
{
System.out.println("\nUnderflow\n");
return;
}
System.out.print("\nThe element removed is "+p.info);
front=front.next;
if(front==null)
rear=null;
display();
}/*end removee*/
}
//--------------------------------------------------------------------------------------------------------------
class LLQueue
{
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.print("\n\nInsert: " + j);
L.insert(j);
}
//L.display();
for(i=0;i<3;i++)
L.remove();
for(i=0;i<2;i++)
{
j = new Integer((int)(Math.random() * 100));
System.out.print("\n\nInsert: " + j);
L.insert(j);
}
}/*end main*/
}


/*
Sample Input and Output :
Insert: 32
front-->32<--rear


Insert: 72
front-->32-->72<--rear


Insert: 10
front-->32-->72-->10<--rear


Insert: 88
front-->32-->72-->10-->88<--rear


Insert: 14
front-->32-->72-->10-->88-->14<--rear


The element removed is 32
front-->72-->10-->88-->14<--rear


The element removed is 72
front-->10-->88-->14<--rear


The element removed is 10
front-->88-->14<--rear


Insert: 11
front-->88-->14-->11<--rear


Insert: 27
front-->88-->14-->11-->27<--rear
*/