我需要一些帮助来理解一些涉及 C++ 中的链接列表的代码

Question

This might be a very dumb question. I have an assignment to create a new node and add a value to it. I've been looking for help online and I came across this code:

head = new(struct node);

I assume it is a way of creating a new node and assigning it to head, right? Is it just a simpler way of writing this?

node *new_node = new node;
head = new_node;

Thanks

Answer 1

That is correct. head = new(struct node); is using the assingment operator and safes you one line compared to

node *new_node = new node; head = new_node; .

I am not sure but I think modern compilers even optimize both inputs to the same assembly code, but you acutually should use head = new(struct node); because it is more readable.

Answer 2

The struct is unnecessary:

head = new node;

is all you need to write. Conventionally you'd add brackets to be more consistent with classes with parameters in their constructors:

head = new node();

This is identical to your second example of creating in a temporary value then copying into head . Most compilers will optimise away the temporary value.