Question

我无法按数字顺序将结构插入到链表中。每个结构都有一个“数字”，如下面的代码所示。我试图让编号最小的结构成为列表的头部（即：是“人”指向的结构）。我一整天都在盯着这段代码，我无法弄清楚它有什么问题。任何帮助深表感谢。感谢

Person *addPerson(Person *people, Person *addition, int &numList)
{
if (people == NULL && numList == 0)
{
    people = addition;
    numList++;
    return people;
}
if (people->number >= addition->number)
{
    addition->nextPerson = people;
    people = addition;
    return people;
}
else if (people->number < addition->number && people->nextPerson != NULL)
{
    addPerson(people->nextPerson, addition, numList);
}
else if (people->number < addition->number && people->nextPerson == NULL)
{
    people->nextPerson = addition;
    numList++;
    return people;
}
}

编辑**

int main()
{
Person *blake = new Person;
Person *kyra = new Person;
Person *elon = new Person;
Person *bill = new Person;
Person *people = NULL;

blake->number = 1;
blake->name = "blake";
blake->lastName = "madden";
blake->nextPerson = NULL;

kyra->number = 2;
kyra->name = "kyra";
kyra->lastName = "madden";
kyra->nextPerson = NULL;

elon->number = 3;
elon->name = "elon";
elon->lastName = "musk";
elon->nextPerson = NULL;

bill->number = 4;
bill->name = "bill";
bill->lastName = "gates";
bill->nextPerson = NULL;

int num = 0;
int &numList = num;

people = addPerson(people, blake, numList);

people = addPerson(people, kyra, numList);
people = addPerson(people, elon, numList);
people = addPerson(people, bill, numList);

cout << people->name << '\n' << people->lastName;
}

Answer 1

您没有在第三个addPerson()块中使用if的返回值。尝试：

people->nextPerson = addPerson(people->nextPerson, addition, numList);
return people;

你还需要return people;，否则你将失去你的功能的结束而不返回任何合理的东西（我的编译器警告我，你应该改变你的警告设置，所以你的也是如此）。

通过上述更改，您的代码似乎正常运行。

Answer 2

您永远不会分配返回的头部。它应该是

people->nextPerson = addPerson(people->nextPerson, addition, numList);

Answer 3

你的问题是函数的参数。您希望在递归调用顺序中修改前一个调用方中节点中的指针，但您只是传递下一个节点的指针值。这不允许您实际修改上一个节点的指针成员。

更改您的功能，使其如下所示：

void addPerson(Person** people, Person *addition, int &numList)

然后当您在第三个区块中调用addPerson时，请执行以下操作：

addPerson(&(*(people)->nextPerson), addition, numList);

最后，当您访问people参数时，请确保进行额外的解除引用，例如：

*people = addition;

或

if ((*people)->number >= addition->number)

在链表c ++中添加struct的递归

3 个答案: