tomtsang

package main

import "fmt"

func main() {
	doDBOperations()
}

func connectToDB() {
	fmt.Println("ok, connected to db")

tomtsang

package main

import "fmt"

func trace(s string) string {
	fmt.Println("entering:", s)
	return s
}

func un(s string) {

tomtsang

//下面的代码展示了另一种在调试时使用 defer 语句的手法（示例 6.12 defer_logvalues.go）：

package main

import (
	"io"
	"log"
)

func func1(s string) (n int, err error) {

tomtsang

package main

import "fmt"

func main() {
	result := 0
	for i := 0; i <= 10; i++ {
		result = fibonacci(i)
		fmt.Printf("fibonacci(%d) is: %d\n", i, result)
	}

tomtsang

// 在需要的时候实现一个 where() 闭包函数来打印函数执行的位置：

where := func() {
	_, file, line, _ := runtime.Caller(1)
	log.Printf("%s:%d", file, line)
}
where()
// some code
where()
// some more code

tomtsang

// 应用闭包：将函数作为返回值
// 工厂函数
func MakeAddSuffix(suffix string) func(string) string {
	return func(name string) string {
		if !strings.HasSuffix(name, suffix) {
			return name + suffix
		}
		return name
	}

tomtsang

start := time.Now()
longCalculation()
end := time.Now()
delta := end.Sub(start)
fmt.Printf("longCalculation took this amount of time: %s\n", delta)

tomtsang

package main

import (
	"fmt"
	"time"
)

const LIM = 41

var fibs [LIM]uint64

tomtsang

package main

import "fmt"

func main() {
	s1 := []byte{'p', 'o', 'e', 'm'} //且
	s2 := s1[2:]
	//	s2[1] = 't' // 这个时候, s1, s2 都会改变
	for i := 0; i < len(s1); i++ {
		fmt.Printf("Slice at %d is %v\n", i, s1[i])

tomtsang

package main

import "fmt"

func main() {
	sl_from := []int{1, 2, 3}
	sl3 := []int{1, 2, 3}
	sl3 = append(sl3, 4, 5, 6)
	sl3 = append(sl3, sl_from...)
	fmt.Println(sl3)