为什么这个简单的insert_back代码链表无法正常工作？ [英] Whys is this simple insert_back code for linked list not working fine?

问题描述

我编写了这个函数，用于在链表前插入一个节点。据我说这个代码应该可以工作，但不是。

I had written this function for inserting aa node at front of linked list. According to me this code should work but its not.

struct node* insert_back(struct node*& head, int data){
	struct node* p = head;
	while(p!= NULL){
		p = p->next;
	}
	struct node* new_node = (struct node*)malloc(sizeof(node));
	new_node->data = data;
	new_node->next = NULL;
	p  = new_node;
	return head;
}

推荐答案

您的代码创建一个新节点，设置 p 指向它，但不在任何地方将其添加到列表中。然后将 head 返回给调用者，此时 p 超出范围并丢失。您可以使用调试器逐步执行代码来轻松验证这一点。

Your code creates a new node, setting p to point to it, but not adding it into the list anywhere. You then return head to the caller, at which point p goes out of scope and is lost. You can verify this quite easily by using the debugger to step through the code.

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