C链表-删除元素 [英] C linked lists - deleting element

问题描述

如果我在C中有一个链表，并且我需要编写一个函数，该函数将删除列表中它的一个元素(而不是第一个或最后一个).该列表是一个全局变量，因此在我使用它的任何地方都会被更改.如果我执行while循环以到达正确的位置然后删除该元素，那么由于我必须将头部移至该点，整个列表不会更改吗?

if I have a linked list in C and I need to write a function that will delete one of it's elements in the the list (not the first or last one). The list is a global variable, so anywhere I use it it will be changed. If I do a while loop to get to the correct spot and then delete the element, wont the whole list change because I had to move the head to that point?

在while循环中执行head = head -> next时，指针逐个元素移动，一旦完成，我将无法返回第一个元素. 那么如何删除元素而不删除列表的一部分?

While doing head = head -> next in the while loop, the pointer is moving element by element and I have no way of going back to the first element once I have finished. So how can I delete an element without erasing part of the list?

推荐答案

您不应移动全局头，而应创建一个新的指针，该指针将在遍历列表时用作临时头.

You shouldn't move the global head but rather make a new pointer that will work as a temporary head while iterating through the list.

让我们说列表看起来像这样:

Lets say the list looks like:

A -> B -> C -> D

例如，如果要删除C，则需要迭代到B(并看到它指向C).然后将其保存为C的指针，将其命名为pC，转到C并将其保存为D的指针，将其命名为pD.

If you want to delete C for example, you need to iterate to B (and see that it points to C). Then save it's pointer to C lets call it pC, move on to C and save it's pointer to D lets call it pD.

然后，您只需执行pC = pD即可简单地重新链接列表，以便B现在链接到D并完全跳过C.这样，您就可以从链接列表中删除元素.

Then you can simply re-link the list by doing pC = pD so that B now links to D and skips C entirely. That way you remove an element from a linked list.

您的新列表将为A -> B -> D.

请记住在丢失指向变量的指针之前先将其转储.

Just remember to dump the variable before you lose the pointer to it.

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