From b419d9e7323ce0d502b882a2cee9754085867f1b Mon Sep 17 00:00:00 2001
From: AndreaOrlando23 <64850221+AndreaOrlando23@users.noreply.github.com>
Date: Mon, 4 Oct 2021 07:57:50 +0200
Subject: [PATCH 1/4] [FEAT] first version of queue solution in cpp

---
 .../solutions/aorlando/cpp-version/README.md  |  18 ++
 .../solutions/aorlando/cpp-version/queue.cpp  | 225 ++++++++++++++++++
 2 files changed, 243 insertions(+)
 create mode 100644 challenges/easy/queue/solutions/aorlando/cpp-version/README.md
 create mode 100644 challenges/easy/queue/solutions/aorlando/cpp-version/queue.cpp

diff --git a/challenges/easy/queue/solutions/aorlando/cpp-version/README.md b/challenges/easy/queue/solutions/aorlando/cpp-version/README.md
new file mode 100644
index 0000000..d99dc64
--- /dev/null
+++ b/challenges/easy/queue/solutions/aorlando/cpp-version/README.md
@@ -0,0 +1,18 @@
+# Queue - How does it work?
+
+Queues follow the First-in-First-Out ([FIFO](https://it.wikipedia.org/wiki/FIFO)) principle.
+
+***e.g.*** As if waiting in a queue for the movie tickets, the first one to stand in line is the first one to buy a ticket and enjoy the movie.
+
+I have created a data structure in cpp for a queue able to do the following methods:
+
+  - `enqueue(item)` - adds an item to the queue
+  - `dequeue()` - removes an item from the queue (FIFO)
+  - `peek()` - returns the next item in the queue without removing it
+  - `isEmpty()` - tests to see whether the queue is empty
+  - `size()` - returns the number of items in the queue
+  - `isFull()` - tests to see whether the queue is full
+  - `display()` - return the item inside the queue
+
+  
+  I've also tryed to develop a fancy CLI interface to insert the intructions directly from the user :)
diff --git a/challenges/easy/queue/solutions/aorlando/cpp-version/queue.cpp b/challenges/easy/queue/solutions/aorlando/cpp-version/queue.cpp
new file mode 100644
index 0000000..7e97070
--- /dev/null
+++ b/challenges/easy/queue/solutions/aorlando/cpp-version/queue.cpp
@@ -0,0 +1,225 @@
+#include <iostream>
+using namespace std;
+
+class Queue {
+    private:
+    int front;
+    int rear;
+    int arr[5];
+    int itemCount;
+
+    public:
+    // constructor
+    Queue() {
+        int itemCount = 0;
+        front = -1;
+        rear = -1;
+        for(int i=0; i<5; i++) {
+            arr[i]=0;
+        }
+    }
+
+    void enqueue(int item) {
+        if(isFull()) {
+            cout << "Queue is FULL" << endl;
+            return;
+        }
+        else if(isEmpty()) {
+            rear=0;
+            front=0;
+            arr[rear]=item;
+        }
+        else {
+            /* e.g. 
+            Assume we have added an element in our array that have at least one element already:
+            rear == 0
+            rear + 1 == 1
+            1 % 5 == 1, so rear become == 1
+            then put the new element in the position 1 of our array
+
+            enqueue() again:
+            rear == 1
+            rear + 1 == 2
+            2 % 5 == 2, so rear become == 2
+            then put the new element in the position 2 of our array
+
+            Let's say that we have 5 elements [5 4 3 2 1] in our array so the queue is full.
+            In according to the algorithm, rear is == to 4
+            If we dequeue(), the first element removed is 5
+            then enqueue() the element 6:
+            rear == 4
+            rear + 1 == 5
+            5 % 5 == 0, so rear become == 0
+            then put the new element in the position 0 of our array
+            (see dequeue() method to understand the logic for that process) 
+        */
+            rear = (rear+1)%5;
+            arr[rear]=item;
+            
+        }
+        itemCount++;
+    }
+
+    int dequeue() {
+        int x = 0;
+        if(isEmpty()) {
+            cout << "Queue is EMPTY" << endl;
+            return -1;  //we have to reurn some value couse of the int function
+        }
+        else if(front == rear) {
+            /* 
+            the only chance that could happen is when the arrey has only one element
+            so front and rear come back to the initial situation --> front = rear = -1 
+            */
+            x = arr[front];  // I put the value wich I have to return at the variable x
+            arr[front] = 0;  // I replace the value with a 0
+            front = -1;
+            rear = -1;
+            itemCount--;
+            return x;
+        }
+        else {
+            /* e.g. 
+            Assume we have at least two elements in the array [5 4]:
+            front == 0
+            x = arr[0] --> 5
+            raplace arr[front] with 0 as a placeholder
+
+            (front+1)%5 == 1
+            then front become == 1 
+            in that case, front = rear = 1. So if we dequeue() again, the second condition run
+
+            dequeue() an array with 3 elements [5 4 3]:
+            front == 0
+            x = arr[0] --> 5
+            raplace arr[front] with 0 as a placeholder
+
+            (front+1)%5 == 1
+            then front become == 1 
+            in that case, front = 1 and rear = 2. So if we dequeue() again, the third condition run again
+            
+        */
+            x = arr[front];
+            arr[front] = 0;
+            front = (front+1)%5;
+            itemCount--;
+            return x;
+        }
+    }
+
+    int peek() {
+        if(!isEmpty()) {
+            return arr[front];
+        }
+    }
+
+    bool isEmpty() {
+        if(front==-1 && rear==-1)
+            return true;
+        else
+            return false;
+    }
+
+    int size() {
+        return itemCount;
+    }
+
+    bool isFull() {
+        /* e.g. 
+            Assume we have our array full of elements [5 4 3 2 1]:
+            front == 0
+            rear == 4
+            rear + 1 == 5
+            5 % 5 == 0
+            so (rear+1)%5 == front and then the queue is full and the condition is true
+
+            if we dequeue() one element:
+            front == 1  // (see the dequeue() logic)
+            rear == 4  // it remains the same as before till we enqueue() a new element
+            rear + 1 == 5
+            5 % 5 == 0
+            so (rear+1)%5 != front and then the queue is not full and the condition is false
+        */
+        if((rear+1)%5 == front)
+            return true;
+        else
+            return false;
+    }
+
+    void display() {
+        for(int i=0; i<5; i++) {
+            cout << arr[i] << " ";
+        }
+    }
+
+};
+
+
+int main() {
+
+    Queue test1;
+    int option, item;
+
+    do {
+        cout << "\n\nWhat operation do you want to perform? Select Option number (0 to exit)." << endl;
+        cout << "1. enqueue(item)" << endl;
+        cout << "2. dequeue()" << endl;
+        cout << "3. peek()" << endl;
+        cout << "4. isEmpty()" << endl;
+        cout << "5. size()" << endl;
+        cout << "6. isFull()" << endl;
+        cout << "7. display()" << endl;
+        
+
+        cin >> option;
+
+        switch(option) {
+            case 0:
+                break;
+
+            case 1:
+                cout << "*** Enqueue Operation 1*** \nPlease enter an item to Enqueue in the Queue:"<<endl;
+                cin >> item;
+                test1.enqueue(item);
+                break;
+
+            case 2:
+                cout << "*** Dequeue Operation *** \nDequeued Value: " << test1.dequeue() <<endl;
+                break;
+            
+            case 3:
+                cout << "*** Peek Operation *** \nThe first item is: " << test1.peek() <<endl;
+                break;
+            
+            case 4:
+                if(test1.isEmpty())
+                    cout << "Queue is Empty." << endl;
+                else
+                    cout << "Queue is NOT Empty." << endl;
+                break;
+            
+            case 5:
+                cout << "*** Size Operation *** \nCount of items in Queue: " << test1.size() <<endl;
+                break;
+            
+            case 6:
+                if(test1.isFull())
+                    cout << "Queue is Full." << endl;
+                else
+                    cout << "Queue is NOT Full." << endl;
+                break;
+            
+            case 7:
+                cout << "*** Display Function Called *** \nAll values in the Queue are: ";
+                test1.display();
+                break;
+            
+            default:
+                cout << "Please enter a valid option number. " << endl;
+                break;
+        }
+    }
+    while(option!=0);
+
+    return 0;
+}
\ No newline at end of file

From c70bda363ce4bb0b4a3c375f0362165e5443a2cc Mon Sep 17 00:00:00 2001
From: AndreaOrlando23 <64850221+AndreaOrlando23@users.noreply.github.com>
Date: Sat, 9 Oct 2021 10:58:19 +0200
Subject: [PATCH 2/4] refactor: from PR #51 - implement queue challenge using
 vector data structure

---
 .../solutions/aorlando/cpp-version/README.md  |   1 -
 .../solutions/aorlando/cpp-version/queue.cpp  | 155 +++---------------
 2 files changed, 24 insertions(+), 132 deletions(-)

diff --git a/challenges/easy/queue/solutions/aorlando/cpp-version/README.md b/challenges/easy/queue/solutions/aorlando/cpp-version/README.md
index d99dc64..577f58d 100644
--- a/challenges/easy/queue/solutions/aorlando/cpp-version/README.md
+++ b/challenges/easy/queue/solutions/aorlando/cpp-version/README.md
@@ -11,7 +11,6 @@ I have created a data structure in cpp for a queue able to do the following meth
   - `peek()` - returns the next item in the queue without removing it
   - `isEmpty()` - tests to see whether the queue is empty
   - `size()` - returns the number of items in the queue
-  - `isFull()` - tests to see whether the queue is full
   - `display()` - return the item inside the queue
 
   
diff --git a/challenges/easy/queue/solutions/aorlando/cpp-version/queue.cpp b/challenges/easy/queue/solutions/aorlando/cpp-version/queue.cpp
index 7e97070..39c4210 100644
--- a/challenges/easy/queue/solutions/aorlando/cpp-version/queue.cpp
+++ b/challenges/easy/queue/solutions/aorlando/cpp-version/queue.cpp
@@ -1,162 +1,63 @@
 #include <iostream>
+#include <vector>
 using namespace std;
 
-class Queue {
+
+class Queue 
+{
     private:
-    int front;
-    int rear;
-    int arr[5];
-    int itemCount;
+    vector<int> myQueue;
 
     public:
-    // constructor
-    Queue() {
-        int itemCount = 0;
-        front = -1;
-        rear = -1;
-        for(int i=0; i<5; i++) {
-            arr[i]=0;
-        }
-    }
 
     void enqueue(int item) {
-        if(isFull()) {
-            cout << "Queue is FULL" << endl;
-            return;
-        }
-        else if(isEmpty()) {
-            rear=0;
-            front=0;
-            arr[rear]=item;
-        }
-        else {
-            /* e.g. 
-            Assume we have added an element in our array that have at least one element already:
-            rear == 0
-            rear + 1 == 1
-            1 % 5 == 1, so rear become == 1
-            then put the new element in the position 1 of our array
-
-            enqueue() again:
-            rear == 1
-            rear + 1 == 2
-            2 % 5 == 2, so rear become == 2
-            then put the new element in the position 2 of our array
-
-            Let's say that we have 5 elements [5 4 3 2 1] in our array so the queue is full.
-            In according to the algorithm, rear is == to 4
-            If we dequeue(), the first element removed is 5
-            then enqueue() the element 6:
-            rear == 4
-            rear + 1 == 5
-            5 % 5 == 0, so rear become == 0
-            then put the new element in the position 0 of our array
-            (see dequeue() method to understand the logic for that process) 
-        */
-            rear = (rear+1)%5;
-            arr[rear]=item;
-            
-        }
-        itemCount++;
+        myQueue.push_back(item);
     }
 
     int dequeue() {
         int x = 0;
         if(isEmpty()) {
-            cout << "Queue is EMPTY" << endl;
+            cout << "Queue is Empty." << endl;
             return -1;  //we have to reurn some value couse of the int function
         }
-        else if(front == rear) {
-            /* 
-            the only chance that could happen is when the arrey has only one element
-            so front and rear come back to the initial situation --> front = rear = -1 
-            */
-            x = arr[front];  // I put the value wich I have to return at the variable x
-            arr[front] = 0;  // I replace the value with a 0
-            front = -1;
-            rear = -1;
-            itemCount--;
-            return x;
-        }
         else {
-            /* e.g. 
-            Assume we have at least two elements in the array [5 4]:
-            front == 0
-            x = arr[0] --> 5
-            raplace arr[front] with 0 as a placeholder
-
-            (front+1)%5 == 1
-            then front become == 1 
-            in that case, front = rear = 1. So if we dequeue() again, the second condition run
-
-            dequeue() an array with 3 elements [5 4 3]:
-            front == 0
-            x = arr[0] --> 5
-            raplace arr[front] with 0 as a placeholder
-
-            (front+1)%5 == 1
-            then front become == 1 
-            in that case, front = 1 and rear = 2. So if we dequeue() again, the third condition run again
-            
-        */
-            x = arr[front];
-            arr[front] = 0;
-            front = (front+1)%5;
-            itemCount--;
+            x = myQueue.at(0);
+            myQueue.erase(myQueue.begin());
             return x;
         }
     }
 
     int peek() {
-        if(!isEmpty()) {
-            return arr[front];
-        }
+        if(!isEmpty()) 
+            return myQueue.at(0);
+        else 
+            cout << "Queue is Empty." << endl;
+            return -1;
     }
 
     bool isEmpty() {
-        if(front==-1 && rear==-1)
+        if(myQueue.size() == 0)
             return true;
         else
             return false;
     }
 
     int size() {
-        return itemCount;
-    }
-
-    bool isFull() {
-        /* e.g. 
-            Assume we have our array full of elements [5 4 3 2 1]:
-            front == 0
-            rear == 4
-            rear + 1 == 5
-            5 % 5 == 0
-            so (rear+1)%5 == front and then the queue is full and the condition is true
-
-            if we dequeue() one element:
-            front == 1  // (see the dequeue() logic)
-            rear == 4  // it remains the same as before till we enqueue() a new element
-            rear + 1 == 5
-            5 % 5 == 0
-            so (rear+1)%5 != front and then the queue is not full and the condition is false
-        */
-        if((rear+1)%5 == front)
-            return true;
-        else
-            return false;
+        return myQueue.size();
     }
 
     void display() {
-        for(int i=0; i<5; i++) {
-            cout << arr[i] << " ";
+        if (isEmpty())
+            cout << "|None";
+        cout << "|";
+        for(int i=0; i<myQueue.size(); i++) {
+            cout << myQueue[i] << "|";
         }
     }
-
 };
 
 
 int main() {
-
     Queue test1;
     int option, item;
 
@@ -167,8 +68,7 @@ int main() {
         cout << "3. peek()" << endl;
         cout << "4. isEmpty()" << endl;
         cout << "5. size()" << endl;
-        cout << "6. isFull()" << endl;
-        cout << "7. display()" << endl;
+        cout << "6. display()" << endl;
         
 
         cin >> option;
@@ -188,7 +88,7 @@ int main() {
                 break;
             
             case 3:
-                cout << "*** Peek Operation *** \nThe first item is: " << test1.peek() <<endl;
+                cout << "*** Peek Operation *** \nThe last item inserted in Queue is: " << test1.peek() <<endl;
                 break;
             
             case 4:
@@ -203,14 +103,7 @@ int main() {
                 break;
             
             case 6:
-                if(test1.isFull())
-                    cout << "Queue is Full." << endl;
-                else
-                    cout << "Queue is NOT Full." << endl;
-                break;
-            
-            case 7:
-                cout << "*** Display Function Called *** \nAll values in the Queue are: ";
+                cout << "*** Display Function Called *** \nAll items in the Queue are: ";
                 test1.display();
                 break;
             

From e8ca512351e206d212755c974a334931ccc142a9 Mon Sep 17 00:00:00 2001
From: AndreaOrlando23 <64850221+AndreaOrlando23@users.noreply.github.com>
Date: Sun, 10 Oct 2021 00:22:17 +0200
Subject: [PATCH 3/4] refactor: improve methods logic of Queue class

---
 .../solutions/aorlando/cpp-version/queue.cpp  | 25 ++++++++-----------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/challenges/easy/queue/solutions/aorlando/cpp-version/queue.cpp b/challenges/easy/queue/solutions/aorlando/cpp-version/queue.cpp
index 39c4210..475f198 100644
--- a/challenges/easy/queue/solutions/aorlando/cpp-version/queue.cpp
+++ b/challenges/easy/queue/solutions/aorlando/cpp-version/queue.cpp
@@ -2,7 +2,6 @@
 #include <vector>
 using namespace std;
 
-
 class Queue 
 {
     private:
@@ -17,29 +16,29 @@ class Queue
     int dequeue() {
         int x = 0;
         if(isEmpty()) {
-            cout << "Queue is Empty." << endl;
-            return -1;  //we have to reurn some value couse of the int function
+            cout << "Queue is Empty. The values in queue are: ";
+            return 0;  //we have to return some value couse of the int function
         }
         else {
             x = myQueue.at(0);
             myQueue.erase(myQueue.begin());
+            cout << "Dequeued Value: "; 
             return x;
         }
     }
 
     int peek() {
-        if(!isEmpty()) 
+        if(!isEmpty()) {
+            cout << "The last item inserted is: ";
             return myQueue.at(0);
+        }
         else 
-            cout << "Queue is Empty." << endl;
-            return -1;
+            cout << "Queue is Empty. The values in queue are: ";
+            return 0;
     }
 
     bool isEmpty() {
-        if(myQueue.size() == 0)
-            return true;
-        else
-            return false;
+        return myQueue.size() == 0;
     }
 
     int size() {
@@ -47,8 +46,6 @@ class Queue
     }
 
     void display() {
-        if (isEmpty())
-            cout << "|None";
         cout << "|";
         for(int i=0; i<myQueue.size(); i++) {
             cout << myQueue[i] << "|";
@@ -84,11 +81,11 @@ int main() {
                 break;
 
             case 2:
-                cout << "*** Dequeue Operation *** \nDequeued Value: " << test1.dequeue() <<endl;
+                cout << "*** Dequeue Operation ***\n" << test1.dequeue() <<endl;
                 break;
             
             case 3:
-                cout << "*** Peek Operation *** \nThe last item inserted in Queue is: " << test1.peek() <<endl;
+                cout << "*** Peek Operation ***\n" << test1.peek() <<endl;
                 break;
             
             case 4:

From 1bcce19915934cd5505e2e66cf4b38149f113d94 Mon Sep 17 00:00:00 2001
From: Andrea Orlando <andrea.orlando87@gmail.com>
Date: Tue, 12 Oct 2021 10:26:53 +0200
Subject: [PATCH 4/4] refactor: removed every cout << statement from methods of
 Queue class and improve readability of CLI interface

---
 .../solutions/aorlando/cpp-version/queue.cpp  | 54 +++++++++----------
 1 file changed, 26 insertions(+), 28 deletions(-)

diff --git a/challenges/easy/queue/solutions/aorlando/cpp-version/queue.cpp b/challenges/easy/queue/solutions/aorlando/cpp-version/queue.cpp
index 475f198..0f89a0f 100644
--- a/challenges/easy/queue/solutions/aorlando/cpp-version/queue.cpp
+++ b/challenges/easy/queue/solutions/aorlando/cpp-version/queue.cpp
@@ -14,27 +14,13 @@ class Queue
     }
 
     int dequeue() {
-        int x = 0;
-        if(isEmpty()) {
-            cout << "Queue is Empty. The values in queue are: ";
-            return 0;  //we have to return some value couse of the int function
-        }
-        else {
-            x = myQueue.at(0);
-            myQueue.erase(myQueue.begin());
-            cout << "Dequeued Value: "; 
-            return x;
-        }
+        int x = myQueue.at(0);
+        myQueue.erase(myQueue.begin()); 
+        return x;
     }
 
     int peek() {
-        if(!isEmpty()) {
-            cout << "The last item inserted is: ";
-            return myQueue.at(0);
-        }
-        else 
-            cout << "Queue is Empty. The values in queue are: ";
-            return 0;
+        return myQueue.at(0);
     }
 
     bool isEmpty() {
@@ -45,11 +31,8 @@ class Queue
         return myQueue.size();
     }
 
-    void display() {
-        cout << "|";
-        for(int i=0; i<myQueue.size(); i++) {
-            cout << myQueue[i] << "|";
-        }
+    vector<int> display() {
+        return myQueue;
     }
 };
 
@@ -57,6 +40,7 @@ class Queue
 int main() {
     Queue test1;
     int option, item;
+    vector<int> queue;
 
     do {
         cout << "\n\nWhat operation do you want to perform? Select Option number (0 to exit)." << endl;
@@ -75,17 +59,23 @@ int main() {
                 break;
 
             case 1:
-                cout << "*** Enqueue Operation 1*** \nPlease enter an item to Enqueue in the Queue:"<<endl;
+                cout << "*** Enqueue Operation *** \nPlease add an item to Queue:"<<endl;
                 cin >> item;
                 test1.enqueue(item);
                 break;
 
             case 2:
-                cout << "*** Dequeue Operation ***\n" << test1.dequeue() <<endl;
+                if(test1.isEmpty())
+                    cout << "Queue is Empty" << endl;
+                else
+                    cout << "*** Dequeue Operation ***\nDequeued item: " << test1.dequeue() <<endl;
                 break;
             
             case 3:
-                cout << "*** Peek Operation ***\n" << test1.peek() <<endl;
+                if(test1.isEmpty())
+                    cout << "Queue is Empty" << endl;
+                else
+                    cout << "*** Peek Operation ***\nThe first item inserted in Queue is: " << test1.peek() <<endl;
                 break;
             
             case 4:
@@ -100,8 +90,16 @@ int main() {
                 break;
             
             case 6:
-                cout << "*** Display Function Called *** \nAll items in the Queue are: ";
-                test1.display();
+                if(test1.isEmpty())
+                    cout << "Queue is Empty" << endl;
+                else {
+                    cout << "*** Display Function Called *** \nAll items in the Queue are: ";
+                    queue = test1.display();
+                    cout << "|";
+                    for(int i = 0; i < queue.size(); i++) {
+                        cout << queue[i] << "|";
+                    }
+                }
                 break;
             
             default: