001_Go hello world

一、go获取程序参数及指针地址示例

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package main import (     "fmt"     "os" )   func main()  {     fmt.Println(os.Args);       if len(os.Args) > 1{         fmt.Println("Hi", os.Args[1])     }else {         fmt.Println("Hello world")         os.Exit(3)     }       fmt.Println(*foo()) }     func foo() *string{     s := "Hello arun"     return &s }/* Hi ggg Hello arun */

(1)go run helloworld.go

(2)go build helloworld.go && ./hellowold

注意事项:main函数没有参数和返回值

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package main import (     "fmt"     "os" )   //func main() int { //func main must have no arguments and no return values func main() { //func main must have no arguments and no return values     fmt.Println("Hello arun!")     //return 1     os.Exit(-1) }

二、编写测试go测试程序

1.源码文件以_test结尾: xxx_test.go

2.测试方法名以Test开头: func TestXXX(t *testing.T) {...}

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package fib import (     "fmt"     "testing" )   func TestFibonacciCreation(t *testing.T)  {     //t.Log("Log print") /*  var a int =1     var b = 1     var n  int = 5*/   /*  var (         a int = 1         b  = 1 //自动类型推断         n  int = 5     )*/       var a, b , n= 1, 1, 5       fmt.Print(a)     for i :=0;/*短变量声明 := */ i< n; i++{         fmt.Print(" ", b)         tmp := a         a = b         b = tmp + b     }     fmt.Println() }/* === RUN   TestFibonacciCreation 1 1 2 3 5 8 --- PASS: TestFibonacciCreation (0.00s) PASS */

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