用单链表实现队列

#include 
#include 
#include 
using namespace std;

//队列：先进先出


struct ListNode {
    int val;
    ListNode *next;
    ListNode(int x) : val(x), next() {}
};


class MyQueue {
private:
    ListNode *head;
    ListNode *tail;
    int _size;
public:
    MyQueue() {
        head = NULL;
        tail = NULL;
        _size = 0;
    }

    bool isEmpty() {
        return _size == 0;
    }

    int size() {
        return _size;
    }

    void push(int value) {
        ListNode *cur = new ListNode(value);
        if (tail == NULL) {
            head = cur;
            tail = cur;
        } else {
            tail->next = cur;
            tail = cur;
        }
        _size++;
    }

    int pop() {
        int ans;
        if (head != NULL) {
            ListNode *node = head;
            ans = head->val;
            head = head->next;
            free(node);
            _size--;
        } 
        if (head == NULL) {
            tail = NULL;
        }
        return ans;
    }


    int top() {
        int ans;
        if (head != NULL) {
            ans = head->val;
        }
        return ans;
    }
};


void testQueue() {
    int testTime = 5000000;
    int maxValue = 200000000;

    MyQueue *myQueue = new MyQueue();
    queue<int> test;

    srand(time(0));

    cout << "测试开始:" << endl;

    for (int i = 0; i < testTime; i++) {
        if (myQueue->isEmpty() != test.empty()) {
            cout << "Oops! isEmpty() function is wrong!" << endl;
            break;
        }

        if (myQueue->size() != test.size()) {
            cout << "size() function is wrong!" << endl;
            break;
        }

        double decide = (rand() % 101) / (double)101;

        if (decide < 0.33) {
            int num = rand() % maxValue;
            myQueue->push(num);
            test.push(num);
        } else if (decide < 0.66) {
            if (!myQueue->isEmpty()) {
                int num1 = myQueue->pop();
                int num2 = test.front();
                test.pop();
                if (num1 != num2) {
                    cout << "pop() function is wrong!" << endl;
                    break;
                }
            } 
        } else {
            if (!myQueue->isEmpty()) {
                int num1 = myQueue->top();
                int num2 = test.front();
                if (num1 != num2) {
                    cout << "top() function is wrong!" << endl;
                     break;
                }
            }
        }
    }

    if (myQueue->size() != test.size()) {
        cout << "size() function is wrong2!" << endl;
    }

    while (!myQueue->isEmpty()) {
        int num1 = myQueue->pop();
        int num2 = test.front();
        test.pop();
        if (num1 != num2) {
            cout << "Oops! pop() function is wrong!" << endl;
            break;
        }
    }
    
    cout << "测试结束!" << endl;
}


int main() {
    testQueue();
    return 0;
}