从C++开始（请温柔点）。 我有一些代码，我必须:

• 添加元素*以创建双链表
• 将insert_before()和insert_after()方法添加到元素
• 使用两个单独的for-循环双向遍历列表
• 打印每个循环内的操作编号

代码

我尝试了以下操作:

#include <cstdio>

struct Element {
    Element* next{};
    Element* previous{};

    void insert_after(Element* new_element) {
        new_element -> previous = this;
        new_element -> next = this -> next;
        this -> next = new_element;
    }
    void insert_before(Element* new_element) {
        new_element -> previous = this -> previous;
        new_element -> next = this;
        this -> previous = new_element;
    }
    char prefix[2];
    short operating_number;
};

int main() {
    Element trooper1, trooper2, trooper3, trooper4;
    trooper1.prefix[0] = 'T';
    trooper1.prefix[1] = 'K';
    trooper1.operating_number = 421;
    trooper1.insert_after(&trooper2);
    trooper2.prefix[0] = 'F';
    trooper2.prefix[1] = 'N';
    trooper2.operating_number = 2187;
    trooper2.insert_before(&trooper3);
    trooper3.prefix[0] = 'L';
    trooper3.prefix[1] = 'S';
    trooper3.operating_number = 005;
    trooper3.insert_before(&trooper4);
    trooper4.prefix[0] = 'F';
    trooper4.prefix[1] = 'K';
    trooper4.operating_number = 2602;

    for (Element *cursor = &trooper1; cursor; cursor = cursor -> next) {
        printf("stormtrooper %c%c-%d\n",
                cursor->prefix[0],
                cursor->prefix[1],
                cursor->operating_number);
    }
    for (Element *cursor = &trooper3; cursor; cursor = cursor -> previous) {
        printf("stormtrooper %c%c-%d\n",
               cursor->prefix[0],
               cursor->prefix[1],
               cursor->operating_number);
    }
}

很基本，我知道。 但我开始学了。 代码编译正确，但我得到以下输出:

/home/facundo/Escritorio/C++Projects/cmake-build-debug/C__Projects
stormtrooper TK-421
stormtrooper FN-2187
stormtrooper LS-5
stormtrooper FK-2602
stormtrooper TK-421

Process finished with exit code 0

我真的不明白为什么它只打印那个（我猜应该有8行输出）。 我期望输出将打印如下元素:

兵种1

第4分队

兵种3

兵种2

兵种2

兵种3

第4分队

兵种1

如果你能帮上忙，我会非常感激的。 谢谢你慢慢来。