Update stack.md and queue.md

Author: krahets

docs/chapter_stack_and_queue/queue.md

@@ -328,15 +328,14 @@ comments: true
             queSize++;
         }
         /* 出队 */
-        int poll() {
+        void poll() {
             int num = peek();
             // 删除头结点
             ListNode *tmp = front;
             front = front->next;
             // 释放内存
             delete tmp; 
             queSize--;
-            return num;
         }
         /* 访问队首元素 */
         int peek() {
@@ -719,11 +718,10 @@ comments: true
             rear = (rear + 1) % capacity();
         }
         /* 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 */
         int peek() {

docs/chapter_stack_and_queue/stack.md

@@ -313,14 +313,13 @@ comments: true
             stkSize++;
         }
         /* 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 */
         int top() {
@@ -657,10 +656,9 @@ comments: true
             stack.push_back(num);
         }
         /* 出栈 */
-        int pop() {
+        void pop() {
             int oldTop = top();
             stack.pop_back();
-            return oldTop;
         }
         /* 访问栈顶元素 */
         int top() {