adding the queue stack problems

leetcode/p225_stack_using_queues.cpp

@@ -0,0 +1,40 @@
+class MyStack {
+public:
+    MyStack() {
+        
+    }
+    
+    void push(int x) {
+        que.push(x);
+        int size = que.size();
+        for(int i=0;i<size-1;i++){
+            que.push(que.front());
+            que.pop();
+        }
+    }
+    
+    int pop() {
+        int x = que.front();
+        que.pop();
+        return x;
+    }
+    
+    int top() {
+        return que.front();
+    }
+    
+    bool empty() {
+        return que.empty();
+    }
+private:
+    std::queue<int> que;
+};
+
+/**
+ * Your MyStack object will be instantiated and called as such:
+ * MyStack* obj = new MyStack();
+ * obj->push(x);
+ * int param_2 = obj->pop();
+ * int param_3 = obj->top();
+ * bool param_4 = obj->empty();
+ */