Queue Implementation with link list

Algoritm ::

Q <= x  : // enqueue operation

                l ← getcell

                if l = nil then overflow

                else

                      info ( l ) ← x

                      link ( l ) ← nil

                      link (r ) ← l

                       r ← l

x <= Q : // dequeue operation

                t ← link ( f )

                if t = nil then underflow

                else

                      x ← info ( t )

                      link ( f ) ← link ( t )

CODE ::

#include <iostream>

#include <cstdlib>

using namespace std;

struct node{

    int data;

    struct node *link;

}*t,*r,*f;

void enqueue(int x)

{

    node *l = (node*) malloc(sizeof(node));

    l->data = x;

    l->link = NULL;

    r->link = l;

    r=l;

}

int dequeue()

{

    t=f->link;

    if(t==NULL)

    {

        cout<<"Underflow"<<endl;

        exit(0);

    }

    int x = t->data;

    f->link = t->link;

    return x;

}

int main()

{

    node *head = (node*) malloc(sizeof(node));

    r=head;

    f=head;

    for(int i=0;i<5;i++)

    {

        int x= rand()%100;

        enqueue(x);

    }

    for(int i=0;i<5;i++)

    {

        cout<<dequeue()<<" ";

    }

}