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Queue impementation using Linked list.cpp
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Queue impementation using Linked list.cpp
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// Queue implementation using Linked list
#include <iostream>
#include <cstdlib>
template <typename T>
class Queue{
private:
class Node{
public:
T data;
Node* next;
Node(){next = NULL;}
Node(const T& cpy){
data = cpy;
next = NULL;
}
};
Node *head, *tail;
int nodeCount;
public:
//default constructor
Queue(){
head= tail= NULL;
nodeCount= 0;
}
//copy constructor
Queue(Queue& cpy){
if(cpy.empty()){
head= tail= NULL;
nodeCount= 0;
return;
}
head= tail= new Node(cpy.head->data);
for(Node* i= cpy.head->next; i!=NULL; i= i->next){
push(i->data);
}
}
int size(){
return nodeCount;
}
bool empty(){
return nodeCount == 0;
}
void push(const T& cpy){
//if queue if empty
if(nodeCount == 0){
head= tail= new Node(cpy);
}
else{
tail->next = new Node(cpy);
tail = tail->next;
}
nodeCount++;
}
void pop(){
if(nodeCount == 0){
std::cerr<< "Queue underflow error!\n";
return;
}
Node* temp= head;
head= head->next;
delete temp;
nodeCount--;
}
T& front() const{
if(nodeCount == 0){
std::cerr<< "Queue underflow error!\n";
exit(1);
}
return head->data;
}
T& rear() const{
if(nodeCount == 0){
std::cerr<< "Queue underflow error!\n";
exit(1);
}
return tail->data;
}
void clear(){
//if Queue is already empty
if(nodeCount == 0) return;
Node* i= head;
Node* temp;
while(i != NULL){
temp= i->next;
delete i;
i= temp;
}
head= tail= NULL;
nodeCount= 0;
}
//for testing
void print(){
for(Node* i= head; i!=NULL; i= i->next){
std::cout<< i->data <<" ";
}
std::cout<<std::endl;
}
~Queue(){
clear();
}
};
//std::cout<< "AAAAAAAAA"<<std::endl;
int main(void)
{
using namespace std;
Queue<int> q;
q.push(1);
q.push(2);
q.push(3);
q.push(4);
q.push(5);
q.pop();
q.push(4);
// cout<< q.rear() <<endl;
q.clear();
Queue<int> qq(q);
qq.print();
return 0;
}