直接将结构传递给功能

Question

I have a struct that I initialize like this:

typedef struct
{
 word w;
 long v;
}
MyStruct;


MyStruct sx = {0,0};
Update(sx);

Now, it seems such a waste to first declare it and then to pass it. I know that in C#, there's a way to do everything in one line. Is there any possiblity of passing it in a more clever (read: cleaner) way to my update function?

Answer 1

In C++, structs are the same as classes except in structs everything is public by default. So you can give a struct a constructor, eg

struct MyStruct
{
 word w;
 long v;

 MyStruct(word w, long v) : w(w), v(v) {}
};


Update(MyStruct(0,0));

Also, C-style struct typedef'ing is unnecessary and discouraged in C++.

Answer 2

It depends on how your Update is declared. If it expects a value of MyStruct type or a reference of const MyStruct& type, you can just do

Update(MyStruct());

This is possible because you wanted to initialize your object with zeroes (which is what the () initializer will do in this case). If you needed different (non-zero) initializer values, you have to either provide a constructor for MyStruct or do it the way you do it in your question (at least in the current version of the C++ language).