Go 杂谈

// h.go
package main
import (
	"fmt"
	"runtime"
)
func adder() func(int) int {
	sum := 0
	return func(x int) int {
		sum += x
		return sum
	}
}
type Person struct {
	Name string
	Age uint8
}
/*
func (P Person) String() string {
	return fmt.Sprintf("%v (%v years)", P.Name, P.Age)
}
*/
func (P *Person) String() string {
	return fmt.Sprintf("%v (%v years)", P.Name, P.Age)
}
func main() {
	for skip := 0; ; skip++ {
		pc, file, line, ok := runtime.Caller(skip)
		if !ok {
			break
		}
		fmt.Printf("skip = %v, pc = %v, file = %v, line = %v\n", skip, pc, file, line)
	}
	//switch
	fmt.Print("Go runs on ")
	switch os := runtime.GOOS; os {
	case "darwin":
		fmt.Println("OS X.")
	case "linux":
		fmt.Println("Linux.")
	default:
		fmt.Printf("%s.\n", os)
	}
	//defer
	fmt.Println("counting ")
	for i := 0; i < 10; i++ {
		defer fmt.Println(i * 10)
	}
	fmt.Println("done")
	//指针
	var i, j int = 42, 27
	p := &i
	fmt.Println("*p= ", *p)
	*p = 21
	fmt.Println("i = ", i)
	p = &j
	*p = *p / 3
	fmt.Println("j = ", j)
	//闭包
	pos, neg := adder(), adder()
	for i := 0; i < 10; i++ {
		fmt.Println("pos = ", pos(i), "neg = ", neg(-i))
	}
	//interface
	tom := &Person{"Tom", 22} //Person{"Tom", 22}
	cat := &Person{"cat", 33} //Person{"cat", 33}
	fmt.Println(tom, cat)
}

输出结果:

skip = 0, pc = 4763241, file = C:/Go/mycode/20170508/1/h.go, line = 34
skip = 1, pc = 4366150, file = C:/Go/src/runtime/proc.go, line = 185
skip = 2, pc = 4513537, file = C:/Go/src/runtime/asm_amd64.s, line = 2197
Go runs on windows.
counting 
done
*p= 42
i = 21
j = 9
pos = 0 neg = 0
pos = 1 neg = -1
pos = 3 neg = -3
pos = 6 neg = -6
pos = 10 neg = -10
pos = 15 neg = -15
pos = 21 neg = -21
pos = 28 neg = -28
pos = 36 neg = -36
pos = 45 neg = -45
Tom (22 years) cat (33 years)
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本文来自:开源中国博客

感谢作者:痞子汤

查看原文:Go 杂谈

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