Use of go function

be familiar with Go The syntax structure of a function

because GO There is no concept of a class , So use structure to simulate . The function in the code calculates the square root of two integers and takes the absolute value of the value .

package main

import (
	"fmt"
	"math"
)

type MyFloat float64
type Vertex struct {
	X, Y float64
}

//Vertex The pointer corresponds to Abs Method 
func (v *Vertex) Abs() float64 {
	return math.Sqrt(v.X*v.X + v.Y*v.Y)
}

//MyFloat Structure corresponding to Abs Method 
func (f MyFloat) Abs() float64 {
	if f < 0 {
		return float64(-f)
	}
	return float64(f)
}

func main() {
	v := &Vertex{6, 4} // obtain Vertex Pointer to structure 
	fmt.Println(v.Abs())
	f := MyFloat(-math.Sqrt2) // take 2 The square root of 
	fmt.Println("float Abs=", f.Abs())
}

The meaning of defining the corresponding method here is that it operates on the original object . If it is defined as the method corresponding to the structure type , It means that the passed parameter is a copy of the structure , Not the original object . We can add Add Method , As shown below ：

package main

import (
	"fmt"
	"math"
)

type MyFloat float64
type Vertex struct {
	X, Y float64
}

//Vertex The pointer corresponds to Abs Method 
func (v *Vertex) Abs() float64 {
	return math.Sqrt(v.X*v.X + v.Y*v.Y)
}

//Vertex The pointer corresponds to Add Method 
func (v *Vertex) Add(f float64) {
	v.X += f
	v.Y += f
}

//MyFloat Structure corresponding to Abs Method 
func (f MyFloat) Abs() float64 {
	if f < 0 {
		return float64(-f)
	}
	return float64(f)
}

func main() {
	v := &Vertex{6, 4} // obtain Vertex Pointer to structure 
	fmt.Println(v.Abs())
	v.Add(3.14)
	fmt.Println(v)
	f := MyFloat(-math.Sqrt2) // take 2 The square root of 
	fmt.Println("float Abs=", f.Abs())
}

After running , object v Inside X and Y The value of .