Question

我正在尝试按照第一个元素对节点进行排序，并且我不断切换不同的节点＆＃39;第一个元素与其他节点的第二和第三个元素。

My goal: 
1, 1, 1 -> 2, 2, 2 -> NULL

My actual outcome:
1, 2, 2 -> 2, 1, 1-> NULL

在打印前比较指针和理解排序时，我感到非常困惑。我的显示功能：

void display()
{
    struct node *s, *ptr;
    int value;
    if (start == NULL)
    {
        cout<<"Try Again";
    }

    ptr = head;
    cout<<"Elements of list are: ";
    while (ptr != NULL)
    {
        for (s = ptr->next; s !=NULL; s = s->next)
        {
            if (ptr->x > s->x)
            {
                value = ptr->x, ptr->y, ptr->z;
                ptr->x, ptr->y, ptr->z = s->x, s->y, s->z;
                s->x, s->y, s->y = value;
            }
            cout<< ptr->x <<", "<< ptr->y <<", "<<ptr->z << " -> ";
        }
        ptr = ptr->next;
    }
    cout<<"NULL";
}

Answer 1

您可能对基本理解C ++中的赋值存在问题。我建议你稍微复习一下c ++，以便更好地理解。

逗号运算符具有任何C运算符的最低优先级，并充当序列点。

示例：

value = ptr->x, ptr->y, ptr->z;
ptr->x, ptr->y, ptr->z = s->x, s->y, s->z;
s->x, s->y, s->y = value;

如果细分，上面的代码实际上是这样的：

value = ptr->x; // Assignment occurring and the other ptr's following the first comma are being discarded

ptr->z = s->x; // Assignment occurring and the other ptr's following the first comma are being discarded

s->y = value; // Assignment occurring and the other ptr's following the first comma are being discarded

Wiki有一个很好的教程：https://en.wikipedia.org/wiki/Comma_operator#Syntax

Answer 2

你应该尝试在纸上写下你的指针以理解它们。

使用多个元素的节点对链表进行排序

2 个答案: