Question

我可以打印一个字符串。但是当我尝试添加两个字符串时，它只打印第一个字符串？ curr是链表的开头。如果我添加一个国家并告诉程序打印它将打印该国家的信息。但是，如果我添加两个国家/地区，它只会打印第一个国家/地区。

 void LinkedList::printList()
 {
    curr = head;
    while (curr)
    {
        cout << "Country Name: " << curr->name << ", " << "Gold: "  << curr->
        gold << ", " << "Silver: " << curr->silver << ", " << "Bronze: " << curr->bronze << "\n";
        curr = curr->next;
    }
}

bool LinkedList::addCountry(string newName, int gold, int silver, int bronze) {
    if (head == NULL)// Adding first element
    {
        head = new struct Country;
        if (head == NULL) return false; // could not create head linked list country
        head->name = newName;
        head->gold = gold;
        head->silver = silver;
        head->bronze = bronze;
        head->next = NULL;
        return true;
    } else {
        curr = head;
        while (curr) {
            curr = curr->next;
        }
        curr = new struct Country;
        if (curr == NULL)
            return false;
        curr->name = newName;
        curr->gold = gold;
        curr->silver = silver;
        curr->bronze = bronze;
        curr->next = NULL;
        return true;
    }
}

Answer 1

@Barmak Shemirani是对的。我想如果你有一个尾巴会员会更好：

  class LindedList
    {
    public:
        LindedList()
        {
            tail=head=curr=NULL;
        };
        Country* head;
        Country* curr;
        Country* tail;
     void printList()
     {
        curr = head;
        while (curr)
        {
            cout << "Country Name: " << curr->name << ", " << "Gold: "  << curr->
            gold << ", " << "Silver: " << curr->silver << ", " << "Bronze: " << curr->bronze << "\n";
            curr = curr->next;
        }
    };

    bool addCountry(string newName, int gold, int silver, int bronze) 
    {
        curr = new Country;
        if (curr == NULL)
                return false;
        curr->name = newName;
        curr->gold = gold;
        curr->silver = silver;
        curr->bronze = bronze;
        curr->next = NULL;
        if (head == NULL)
        {
            head = curr;
            tail=curr;

        } else 
        {
            tail->next=curr;
            tail=curr;

        }
        return true;
    };
    };

Answer 2

printList是正确的。但是在addCountry中，最后一个元素必须指向刚刚插入的新元素。例如：

bool LinkedList::addCountry(string newName, int gold, int silver, int bronze) 
{
    Country *newNode = new Country;
    newNode->name = newName;
    newNode->gold = gold;
    newNode->silver = silver;
    newNode->bronze = bronze;
    newNode->next = NULL;

    if (head == NULL)
    {
        //adding first element:
        head = newNode;
    }
    else 
    {
        //find the last element currently in the list:
        Country *last = head;
        while (last->next)//<= ***** edited
            last = last->next;

        //set newNode as the new last element:
        last->next = newNode;
    }
    return true;
}

同样在C ++中，您可以简单地编写new Country，它不需要struct个关键字。

为什么我不能打印多个字符串？

2 个答案: