Update cpp codes for the stack and the queue.

codes/cpp/chapter_stack_and_queue/array_queue.cpp

@@ -50,11 +50,10 @@ public:
     }
 
     /* 出队 */
-    int poll() {
+    void poll() {
         int num = peek();
         // 队头指针向后移动一位，若越过尾部则返回到数组头部
         front = (front + 1) % capacity();
-        return num;
     }
 
     /* 访问队首元素 */
@@ -98,8 +97,8 @@ int main() {
     cout << "队首元素 peek = " << peek << endl;
     
     /* 元素出队 */
-    int poll = queue->poll();
-    cout << "出队元素 poll = " << poll << "，出队后 queue = ";
+    queue->poll();
+    cout << "出队元素 poll = " << peek << "，出队后 queue = ";
     PrintUtil::printVector(queue->toVector());
 
     /* 获取队列的长度 */

codes/cpp/chapter_stack_and_queue/array_stack.cpp

@@ -28,10 +28,9 @@ public:
     }
 
     /* 出栈 */
-    int pop() {
+    void pop() {
         int oldTop = top();
         stack.pop_back();
-        return oldTop;
     }
 
     /* 访问栈顶元素 */
@@ -67,8 +66,8 @@ int main() {
     cout << "栈顶元素 top = " << top << endl;
 
     /* 元素出栈 */
-    int pop = stack->pop();
-    cout << "出栈元素 pop = " << pop << "，出栈后 stack = ";
+    stack->pop();
+    cout << "出栈元素 pop = " << top << "，出栈后 stack = ";
     PrintUtil::printVector(stack->toVector());
 
     /* 获取栈的长度 */

codes/cpp/chapter_stack_and_queue/linkedlist_queue.cpp

@@ -47,7 +47,7 @@ public:
     }
 
     /* 出队 */
-    int poll() {
+    void poll() {
         int num = peek();
         // 删除头结点
         ListNode *tmp = front;
@@ -55,7 +55,6 @@ public:
         // 释放内存
         delete tmp; 
         queSize--;
-        return num;
     }
 
     /* 访问队首元素 */
@@ -97,8 +96,8 @@ int main() {
     cout << "队首元素 peek = " << peek << endl;
 
     /* 元素出队 */
-    int poll = queue->poll();
-    cout << "出队元素 poll = " << poll << "，出队后 queue = ";
+    queue->poll();
+    cout << "出队元素 poll = " << peek << "，出队后 queue = ";
     PrintUtil::printVector(queue->toVector());
 
     /* 获取队列的长度 */

codes/cpp/chapter_stack_and_queue/linkedlist_stack.cpp

@@ -37,14 +37,13 @@ public:
     }
 
     /* 出栈 */
-    int pop() {
+    void pop() {
         int num = top();
         ListNode *tmp = stackTop;
         stackTop = stackTop->next;
         // 释放内存
         delete tmp;
         stkSize--;
-        return num;
     }
 
     /* 访问栈顶元素 */
@@ -86,8 +85,8 @@ int main() {
     cout << "栈顶元素 top = " << top << endl;
 
     /* 元素出栈 */
-    int pop = stack->pop();
-    cout << "出栈元素 pop = " << pop << "，出栈后 stack = ";
+    stack->pop();
+    cout << "出栈元素 pop = " << top << "，出栈后 stack = ";
     PrintUtil::printVector(stack->toVector());
 
     /* 获取栈的长度 */