在新的声明中设置值

Question

Is it possible to include values in the declaration of a new type.

type Vertex struct {
    X, Y int
}

func main() {
    v := new( Vertex{ 0, 0} ) // Like so
    fmt.Println( v )
    // Instead of :
    v = new(Vertex) 
    v.X, v.Y = 12, 4 // extra line for initializing the values of X and Y 

    fmt.Println( v )
}

Or because go makes the "Vertex{val, val} " a literal value instead of a basic Vertex type it's not possible?

Answer 1

You don't actually need "new", you can simply write:

v := Vertex{1,2}

If you want a struct with all members set to the zero value of their types (e.g., 0 for ints, nil for pointers, "" for strings, etc.), it's even simpler:

v := Vertex{} // same as Vertex{0,0}

You can also only initialize some of the members, leaving the others with their zero value:

v := Vertex{Y:1} // same as Vertex{0,1}

Note that with these v will be a variable of type Vertex. If you want a pointer to a Vertex, use:

v := &Vertex{1,2}