feat: Moving queue file to it's directory and creating include file for it (#874)

* Putting queue in correct dir and creating include file for it

* Update data_structures/queue/include.h

missing one function, added

Co-authored-by: David Leal <halfpacho@gmail.com>

Co-authored-by: David Leal <halfpacho@gmail.com>

data_structures/queue/include.h

@@ -0,0 +1,28 @@
+//////////////////////////////////////////////////////////////////////////////////////
+/// INCLUDES
+
+#include <stdio.h>
+#include <stdlib.h>
+////////////////////////////////////////////////////////////////////////////////
+// DATA STRUCTURES
+/**
+ * Defining the structure of the node which contains 'data' (type : integer),
+ * two pointers 'next' and 'pre' (type : struct node).
+ */
+
+struct node
+{
+    int data;
+    struct node *next;
+    struct node *pre;
+} * head, *tail, *tmp;
+
+////////////////////////////////////////////////////////////////////////////////
+// FORWARD DECLARATIONS
+
+void create();
+void enque(int x);
+int deque();
+int peek();
+int size();
+int isEmpty();

data_structures/queue/queue.c

@@ -1,36 +1,11 @@
 ////////////////////////////////////////////////////////////////////////////////
 // INCLUDES
-#include <stdio.h>
+#include "include.h";
-#include <stdlib.h>
-
-////////////////////////////////////////////////////////////////////////////////
-// MACROS: CONSTANTS
-
-////////////////////////////////////////////////////////////////////////////////
-// DATA STRUCTURES
-/**
- * Defining the structure of the node which contains 'data' (type : integer), two pointers 'next' and 'pre' (type : struct node).
- */
-struct node                                          
-{
-    int data;
-    struct node *next;
-    struct node *pre;
-} * head, *tail, *tmp;
 
 ////////////////////////////////////////////////////////////////////////////////
 // GLOBAL VARIABLES
 int count;
 
-////////////////////////////////////////////////////////////////////////////////
-// FORWARD DECLARATIONS
-void create();
-void enque(int x);
-int deque();
-int peek();
-int size();
-int isEmpty();
-
 ////////////////////////////////////////////////////////////////////////////////
 // MAIN ENTRY POINT