Add a simple queue class

data_structure/queue/makefile

@@ -0,0 +1,11 @@
+CC= g++
+CFLAGS = -c -Wall
+
+all: test_queue
+queue.o: queue.cpp
+	$(CC) $(CFLAGS) queue.cpp
+test_queue: queue.o
+	$(CC) test_queue.cpp queue.o -o queue
+
+clean:
+	rm *o queue

data_structure/queue/queue.cpp

@@ -0,0 +1,90 @@
+#include <iostream>
+#include <assert.h>
+#include "queue.h"
+
+using namespace std;
+
+/* Default constructor*/
+template <class Kind>
+queue<Kind>::queue()
+{
+    queueFront = NULL;
+    queueRear = NULL;
+    size = 0;
+}
+
+/* Destructor */
+template <class Kind>
+queue<Kind>::~queue()
+{
+}
+
+/* Display for testing */
+template <class Kind>
+void queue<Kind>::display()
+{
+    node<Kind> *current = queueFront;
+    cout << "Front --> ";
+    while(current != NULL) {
+        cout<<current->data<< "    ";
+        current = current -> next;
+    }
+    cout <<endl;
+    cout << "Size of queue: " << size << endl;
+}
+
+/* Determine whether the queue is empty */
+template <class Kind>
+bool queue<Kind>::isEmptyQueue()
+{
+    return (queueFront == NULL);
+}
+
+/* Clear queue */
+template <class Kind>
+void queue<Kind>::clear()
+{
+    queueFront = NULL;
+}
+
+/* Add new item to the queue */
+template <class Kind>
+void queue<Kind>::enQueue(Kind item)
+{
+    node<Kind> *newNode;
+    newNode = new node<Kind>;
+    newNode->data = item;
+    newNode->next = NULL;
+    if (queueFront == NULL) {
+        queueFront = newNode;
+        queueRear = newNode;
+    } else {
+        queueRear->next = newNode;
+        queueRear = queueRear->next;
+    }
+    size++;
+}
+
+/* Return the top element of the queue */
+template <class Kind>
+Kind queue<Kind>::front()
+{
+    assert(queueFront != NULL);
+    return queueFront->data;
+}
+
+/* Remove the element of the queue */
+template <class Kind>
+void queue<Kind>::deQueue()
+{
+    node<Kind> *temp;
+    if(!isEmptyQueue()) {
+        temp = queueFront;
+        queueFront = queueFront->next;
+        delete temp;
+        size--;
+    } else {
+        cout << "Queue is empty !" << endl;
+    }
+}
+

data_structure/queue/queue.h

@@ -0,0 +1,34 @@
+/* This class specifies the basic operation on a queue as a linked list */
+#ifndef QUEUE_H
+#define QUEUE_H
+
+/* Definition of the node */
+template <class Kind>
+struct node
+{
+    Kind data;
+    node<Kind> *next;
+};
+
+/* Definition of the queue class */
+template <class Kind>
+class queue
+{
+    public:
+        void display();        /* Show queue */
+        queue();               /* Default constructor*/
+        ~queue();              /* Destructor */
+        bool isEmptyQueue();   /* Determine whether the queue is empty */
+        void enQueue (Kind item); /* Add new item to the queue */
+        Kind front();            /* Return the first element of the queue */
+        void deQueue();        /* Remove the top element of the queue */
+        void clear();
+
+    private:
+        node<Kind> *queueFront;  /* Pointer to the front of the queue */
+        node<Kind> *queueRear;   /* Pointer to the rear of the queue  */
+        int size;
+};
+
+#endif
+

data_structure/queue/test_queue.cpp

@@ -0,0 +1,38 @@
+#include <iostream>
+#include <string>
+#include "queue.h"
+#include "queue.cpp"
+
+using namespace std;
+
+int main()
+{
+    queue<string> q;
+    cout << "---------------------- Test construct ----------------------" << endl;
+    q.display();
+    cout << "---------------------- Test isEmptyQueue ----------------------" << endl;
+    if(q.isEmptyQueue())
+        cout << "PASS" <<endl;
+    else
+        cout << "FAIL" <<endl;
+    cout << "---------------------- Test enQueue ----------------------" << endl;
+    cout << "After Hai, Jeff, Tom, Jkingston go into queue: "<<endl;
+    q.enQueue("Hai");
+    q.enQueue("Jeff");
+    q.enQueue("Tom");
+    q.enQueue("Jkingston");
+    q.display();
+    cout << "---------------------- Test front ----------------------" << endl;
+    string value = q.front();
+    if (value == "Hai")
+        cout << "PASS" <<endl;
+    else
+        cout << "FAIL" <<endl;
+    cout << "---------------------- Test deQueue ----------------------" << endl;
+    q.display();
+    q.deQueue();
+    q.deQueue();
+    cout << "After Hai, Jeff left the queue: "<< endl;
+    q.display();
+    return 0;
+}

data_structure/stk/makefile

@@ -1,7 +1,7 @@
 CC= g++
 CFLAGS = -c -Wall
 
-all: clean main test_stack
+all: main test_stack
 stack.o: stack.cpp
 	$(CC) $(CFLAGS) stack.cpp
 test_stack: stack.o