Update Queue

Author: bitdove

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       matrix:
         # Add your projects from 'data-structures'
-        project: [LinkedList, DoublyLinkedList]
+        project: [LinkedList, DoublyLinkedList, Queue]
 
     steps:
     # Step 1: Checkout the repository

README.md

@@ -21,8 +21,9 @@ Remember that each data has its own trade-offs. And you need to pay attention mo
 
 `B` - Beginner, `A` - Advanced
 
-* `B` [Linked List](data-structures/linked-list)
-* `B` [Doubly Linked List](data-structures/doubly-linked-list)
+* `B` [Linked List](data-structures/LinkedList)
+* `B` [Doubly Linked List](data-structures/DoublyLinkedList)
+* `B` [Queue](data-structures/Queue)
 
 ## Algorithms
 

README.zh-CN.md

@@ -18,8 +18,10 @@
 
 `B` - 初学者， `A` - 进阶
 
-* `B` [链表](data-structures/linked-list)
-* `B` [双链表](data-structures/doubly-linked-list)
+* `B` [单链表](data-structures/LinkedList)
+* `B` [双链表](data-structures/DoublyLinkedList)
+* `B` [队列](data-structures/Queue)
+
 
 ## 算法
 

data-structures/Queue/CMakeLists.txt

@@ -14,11 +14,8 @@ include_directories(include)
 # Output executables to the 'bin' directory
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/../bin)
 
-# Add the main library (LinkedList)
-add_library(Queue src/Queue.cpp)
-
 # Add the test executable
-add_executable(test_queue __test__/test_Queue.cpp)
+add_executable(test_Queue __test__/test_Queue.cpp)
 
 # Link the LinkedList library to the test executable
-target_link_libraries(test_queue Queue)
+target_link_libraries(test_Queue)

data-structures/Queue/__test__/test_Queue.cpp

@@ -1 +1,50 @@
-#include "../include/Queue.h"
+#include "../include/Queue.h"
+#include <cassert>
+#include <iostream>
+
+int main(int argc, char* argv[]){
+  Queue<int> que;
+  assert(que.empty() == true);
+  assert(que.size() == 0);
+  std::cout << "Initial test PASSED!" << std::endl;
+  try{
+    que.pop();
+    std::cerr << "pop() throw exception FAILED!" << std::endl;
+  } catch(const std::underflow_error &e){
+    std::cout << "pop() throw an exception PASSED! " << e.what() << std::endl;
+  }
+  que.push(37);
+  assert(que.empty() == false);
+  assert(que.size() == 1);
+  assert(que.front() == que.back());
+  que.pop();
+  assert(que.empty() == true);
+  assert(que.size() == 0);
+  try{
+    que.front();
+    std::cerr << "front() throw exception FAILED!" << std::endl;
+  } catch(const std::underflow_error &e){
+    std::cout << "front() throw an exception PASSED! " << e.what() << std::endl;
+  }
+  try{
+    que.back();
+    std::cerr << "back() throw exception FAILED!" << std::endl;
+  } catch(const std::underflow_error &e){
+    std::cout << "back() throw an exception PASSED! " << e.what() << std::endl;
+  }
+  que.push(13);
+  que.push(23);
+  que.push(31);
+  que.push(7); // 13 23 31 7
+  assert(que.back() == 7);
+  assert(que.front() == 13);
+  assert(que.size() == 4);
+  assert(que.empty() == false);
+  que.pop();
+  que.push(19);
+  que.pop(); // 31 7 19
+  assert(que.back() == 19);
+  assert(que.front() == 31);
+  std::cout << "ALL TEST PASSED!" << std::endl;
+  return 0;
+}

data-structures/Queue/include/Queue.h

@@ -1,7 +1,75 @@
+#ifndef QUEUE_H
+#define QUEUE_H
+
+#include <stdexcept>
+#include <cstddef>
+#include "../../LinkedList/include/LinkedList.h"
+
+/*
+  We're going to implement Queue based on LinkedList since the two
+  structures are quite similar. Namely, they both operate mostly on
+  the elements at the beginning and the end. Compare push/pop
+  operations of Queue with push_back/pop_front operations of LinkedList.
+*/
+
 template <typename T>
 class Queue{
   public:
-    Queue();
-    ~Queue();
+    //Capacity
+    bool empty() const;
+    size_t size() const;
+    // Add
+    void push(const T& value);
+    // Delete
+    void pop();
+    // Check
+    T& front();
+    T& back();
   private:
-};
+    LinkedList<T> list;
+};
+
+//Capacity
+template <typename T>
+bool Queue<T>::empty() const{
+  return list.empty();
+}
+
+template <typename T>
+size_t Queue<T>::size() const{
+  return list.size();
+}
+
+// Add
+template <typename T>
+void Queue<T>::push(const T &value){
+  list.push_back(value);
+}
+
+// Delete
+template <typename T>
+void Queue<T>::pop(){
+  if(empty()){
+    throw std::underflow_error("This Queue is empty");
+  }
+  list.pop_front();
+}
+
+// Check
+template <typename T>
+T& Queue<T>::front(){
+  if(empty()){
+    throw std::underflow_error("This Queue is empty");
+  }
+  return list.front();
+}
+
+template <typename T>
+T& Queue<T>::back(){
+  if(empty()){
+    throw std::underflow_error("This Queue is empty");
+  }
+  return list.back();
+}
+
+#endif // QUEUE_H