33 * @details
44 * Using 2 Queues inside the Stack class, we can easily implement Stack
55 * data structure with heavy computation in push function.
6- *
7- * References used: [StudyTonight](https://www.studytonight.com/data-structures/stack-using-queue)
6+ *
7+ * References used:
8+ * [StudyTonight](https://www.studytonight.com/data-structures/stack-using-queue)
89 * @author [tushar2407](https://github.com/tushar2407)
910 */
10- #include < iostream > // / for IO operations
11- #include < queue > // / for queue data structure
12- #include < cassert > // / for assert
11+ #include < cassert > // / for assert
12+ #include < iostream > // / for IO operations
13+ #include < queue > // / for queue data structure
1314
1415/* *
1516 * @namespace data_strcutres
1819namespace data_structures {
1920/* *
2021 * @namespace stack_using_queue
21- * @brief Functions for the [Stack Using Queue](https://www.studytonight.com/data-structures/stack-using-queue) implementation
22+ * @brief Functions for the [Stack Using
23+ * Queue](https://www.studytonight.com/data-structures/stack-using-queue)
24+ * implementation
2225 */
2326namespace stack_using_queue {
27+ /* *
28+ * @brief Stack Class implementation for basic methods of Stack Data Structure.
29+ */
30+ struct Stack {
31+ std::queue<int64_t > main_q; // /< stores the current state of the stack
32+ std::queue<int64_t > auxiliary_q; // /< used to carry out intermediate
33+ // /< operations to implement stack
34+ uint32_t current_size = 0 ; // /< stores the current size of the stack
35+
2436 /* *
25- * @brief Stack Class implementation for basic methods of Stack Data Structure.
37+ * Returns the top most element of the stack
38+ * @returns top element of the queue
2639 */
27- struct Stack
28- {
29- std::queue<int64_t > main_q; // /< stores the current state of the stack
30- std::queue<int64_t > auxiliary_q; // /< used to carry out intermediate operations to implement stack
31- uint32_t current_size = 0 ; // /< stores the current size of the stack
32-
33- /* *
34- * Returns the top most element of the stack
35- * @returns top element of the queue
36- */
37- int top ()
38- {
39- return main_q.front ();
40- }
40+ int top () { return main_q.front (); }
4141
42- /* *
43- * @brief Inserts an element to the top of the stack.
44- * @param val the element that will be inserted into the stack
45- * @returns void
46- */
47- void push (int val)
48- {
49- auxiliary_q.push (val);
50- while (!main_q.empty ())
51- {
52- auxiliary_q.push (main_q.front ());
53- main_q.pop ();
54- }
55- swap (main_q, auxiliary_q);
56- current_size++;
57- }
58-
59- /* *
60- * @brief Removes the topmost element from the stack
61- * @returns void
62- */
63- void pop ()
64- {
65- if (main_q.empty ()) {
66- return ;
67- }
42+ /* *
43+ * @brief Inserts an element to the top of the stack.
44+ * @param val the element that will be inserted into the stack
45+ * @returns void
46+ */
47+ void push (int val) {
48+ auxiliary_q.push (val);
49+ while (!main_q.empty ()) {
50+ auxiliary_q.push (main_q.front ());
6851 main_q.pop ();
69- current_size--;
7052 }
53+ swap (main_q, auxiliary_q);
54+ current_size++;
55+ }
7156
72- /* *
73- * @brief Utility function to return the current size of the stack
74- * @returns current size of stack
75- */
76- int size ()
77- {
78- return current_size ;
57+ /* *
58+ * @brief Removes the topmost element from the stack
59+ * @returns void
60+ */
61+ void pop () {
62+ if (main_q. empty ()) {
63+ return ;
7964 }
80- };
65+ main_q.pop ();
66+ current_size--;
67+ }
68+
69+ /* *
70+ * @brief Utility function to return the current size of the stack
71+ * @returns current size of stack
72+ */
73+ int size () { return current_size; }
74+ };
8175} // namespace stack_using_queue
8276} // namespace data_structures
8377
8478/* *
8579 * @brief Self-test implementations
8680 * @returns void
8781 */
88- static void test ()
89- {
82+ static void test () {
9083 data_structures::stack_using_queue::Stack s;
91- s.push (1 ); // / insert an element into the stack
92- s.push (2 ); // / insert an element into the stack
93- s.push (3 ); // / insert an element into the stack
94-
95- assert (s.size ()== 3 ); // / size should be 3
96-
97- assert (s.top ()== 3 ); // / topmost element in the stack should be 3
98-
99- s.pop (); // / remove the topmost element from the stack
100- assert (s.top ()== 2 ); // / topmost element in the stack should now be 2
101-
102- s.pop (); // / remove the topmost element from the stack
103- assert (s.top ()== 1 );
104-
105- s.push (5 ); // / insert an element into the stack
106- assert (s.top ()== 5 ); // / topmost element in the stack should now be 5
107-
108- s.pop (); // / remove the topmost element from the stack
109- assert (s.top ()== 1 ); // / topmost element in the stack should now be 1
110-
111- assert (s.size ()== 1 ); // / size should be 1
84+ s.push (1 ); // / insert an element into the stack
85+ s.push (2 ); // / insert an element into the stack
86+ s.push (3 ); // / insert an element into the stack
87+
88+ assert (s.size () == 3 ); // / size should be 3
89+
90+ assert (s.top () == 3 ); // / topmost element in the stack should be 3
91+
92+ s.pop (); // / remove the topmost element from the stack
93+ assert (s.top () == 2 ); // / topmost element in the stack should now be 2
94+
95+ s.pop (); // / remove the topmost element from the stack
96+ assert (s.top () == 1 );
97+
98+ s.push (5 ); // / insert an element into the stack
99+ assert (s.top () == 5 ); // / topmost element in the stack should now be 5
100+
101+ s.pop (); // / remove the topmost element from the stack
102+ assert (s.top () == 1 ); // / topmost element in the stack should now be 1
103+
104+ assert (s.size () == 1 ); // / size should be 1
112105}
113106
114107/* *
@@ -119,8 +112,7 @@ static void test()
119112 * declared above.
120113 * @returns 0 on exit
121114 */
122- int main ()
123- {
115+ int main () {
124116 test (); // run self-test implementations
125117 return 0 ;
126118}
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