Merge pull request #53 from itodotimothy6/add-queue-front-back-functions

Add queue front back functions

queue.md

@@ -4,12 +4,12 @@
 <summary>View contents</summary>
 <ol>
     <li><a href="#pop"><code>pop</code></a></li>
-    <li><a href="#back-queue"><code>back</code></a></li>
+    <li><a href="#back"><code>back</code></a></li>
     <li><a href="#push"><code>push</code></a></li>
     <li><a href="#size-queue"><code>size</code></a></li>
     <li><a href="#swap-queue"><code>swap</code></a></li>
     <li><a href="#empty-queue"><code>empty</code></a></li>
-    <li><a href="#front-queue"><code>front</code></a></li>
+    <li><a href="#front"><code>front</code></a></li>
     <li><a href="#emplace-queue"><code>emplace</code></a></li>
     <li><a href="#queue"><code>queue</code></a></li>
     <li><a href="#~queue"><code>~queue</code></a>
@@ -41,6 +41,27 @@
 ```
 **[Run Code](https://rextester.com/XACN77371)**
 
+# back
+**Description** : back() function is used to reference the last element (i.e the newest element) of the queue. This function can be used to fetch the last element of a queue.
+
+**Example**:
+```cpp
+    // Empty queue
+    std::queue<int> myqueue;
+    
+    // Add elements to queue using push()
+    myqueue.push(2);
+    myqueue.push(5);
+    myqueue.push(4);
+    myqueue.push(1);
+    
+    // Queue becomes 2, 5, 4, 1
+    
+    // Print the last/newest element in the queue
+    std::cout << myqueue.back();
+```
+**[Run Code](https://rextester.com/MJAK44967)**
+
 # push
 **Description** : push() function is used to insert an element at the back of the queue. The element is added to the queue container and the size of the queue is increased by 1.
 
@@ -60,4 +81,25 @@
         myqueue.pop(); 
     } 
 ```
-**[Run Code](https://rextester.com/OEC31098)**
+**[Run Code](https://rextester.com/OEC31098)**
+
+# front
+**Description** : front() function is used to reference the first element (ie. the oldest element) of the queue. This function can be used to fetch the first element of a queue.
+
+**Example**:
+```cpp
+    // Empty queue
+    std::queue<int> myqueue;
+    
+    // Add elements to queue using push()
+    myqueue.push(2);
+    myqueue.push(5);
+    myqueue.push(4);
+    myqueue.push(1);
+    
+    // Queue becomes 2, 5, 4, 1
+    
+    // Print the first/oldest element in the queue
+    std::cout << myqueue.front();
+```
+**[Run Code](https://rextester.com/NHSYM95891)**

queue/back.cpp

@@ -0,0 +1,25 @@
+// Style Guide => https://github.com/Bhupesh-V/30-Seconds-Of-STL/blob/master/CONTRIBUTING.md/#Style Guide
+/*
+ Author : Timothy Itodo
+ Date : 28/05/2019
+ Time : 1:00 PM
+ Description : back() function is used to reference the last element (i.e the newest element) of the queue. This function can be used to fetch the last element of a queue.
+ */
+#include <iostream>
+#include <queue>
+
+int main(){
+    // Empty queue
+    std::queue<int> myqueue;
+
+    // Add elements to queue using push()
+    myqueue.push(2);
+    myqueue.push(5);
+    myqueue.push(4);
+    myqueue.push(1);
+
+    // Queue becomes 2, 5, 4, 1
+
+    // Print the last/newest element in the queue
+    std::cout << myqueue.back();
+}

queue/front.cpp

@@ -0,0 +1,25 @@
+// Style Guide => https://github.com/Bhupesh-V/30-Seconds-Of-STL/blob/master/CONTRIBUTING.md/#Style Guide
+/*
+ Author : Timothy Itodo
+ Date : 28/05/2019
+ Time : 1:00 PM
+ Description : front() function is used to reference the first element (ie. the oldest element) of the queue. This function can be used to fetch the first element of a queue.
+ */
+#include <iostream>
+#include <queue>
+
+int main(){
+    // Empty queue
+    std::queue<int> myqueue;
+
+    // Add elements to queue using push()
+    myqueue.push(2);
+    myqueue.push(5);
+    myqueue.push(4);
+    myqueue.push(1);
+
+    // Queue becomes 2, 5, 4, 1
+
+    // Print the first/oldest element in the queue
+    std::cout << myqueue.front();
+}