Golang Basic Structure Exercises (DAY2)

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Notes:

1 . Any one code file belongs to a package 2 . Import keyword, referencing other packages: import ("FMT") Import ("OS") is often used to write: import (      "FMT"       "OS")3. The Golang executable, package main,     and has only one main entry function 4. The function call in the packet: A. function in the same package, call B. Functions in different packages, by package name + dot + function name to call 5. Package access control rules: uppercase means that the function / variable is an exportable lowercase meaning that the function / variable is private,     Package external cannot access

Practice:

 package main  /*   > The result is: 0+10=101+9=102+8=103+7=104+6=105+5=106+4=107+3=108+2=109+1=1010+0=10  */ import   " fmt   " func list (n  int   for  I: = 0 ; I <= N; I++ {FMT. Printf (  %d+%d=%d\n   ", I, N-i, N)}}func main () {list ( 10 

2. A program contains two packages of add and main, where the add package has two variables: name and age. How do I access the name and age in the main
package?

 package mainimport ( //   fmt   "  a  "    ) func Main () {FMT. Println (  name=:   " , A.name)  // add.age is a lowercase private variable, so the  FMT is not found. Println ( age=:   " 

Main.go

Package addimport (    //_ "go_dev/day2/example2/test") func init () {    "  HelloWorld " Ten} var string     " xxxxx " var int  the

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3. Application of package aliases, developing a program that uses package aliases to access the functions in the package?

Answer with 2 questions

4. Each source file can contain an init function, which is automatically called by the Go Run framework. Develop a program
Demonstrate this feature?

Directory structure

Package Mainimport (//usage of the package alias a    "FMT"a"Go_dev/day2/example2/add") Func main () {//5 Print in the AddFmt. Println ("name=:", A.name)//Add.age is a lowercase private variable, so it cannot be found//6Fmt. Println ("age=:", A.age)}

Main.go

Package Testimport"FMT"varNamestring="This is the test package"varAgeint= +func init () {//1Fmt. Println ("This is a test,init")    //2Fmt. Println ("test.package.name=", Name)//3Fmt. Println ("test.package.age=", age) Age=Ten    //4Fmt. Println ("test.package.age=", age)}

Test.go

Package AddImport (    _"go_dev/day2/example2/test") func init () {     "helloWorld" var      String"xxxxx"varint

Add.go

6. Define two constants man=1 and female=2, get the number of seconds in the current time, and if they can be divisible by female, then
    Print female on the terminal, otherwise print man.

Second: = time. Now (). Unix ()

Package Mainimport ("FMT"    " Time")Const(Mans= Iota +1Female)/*6. Define two constants man=1 and female=2, get the number of seconds in the current time, if divisible by female, print the female at the terminal, otherwise print man. Second: = time. Now (). Unix ()*/Func Main () {//For is a dead loop .     for{time. Sleep (100000*Time . microsecond) Second:=Time . Now (). Unix ()ifSecond%female = =0{fmt. Println ("female")        } Else{fmt. Println ("Mans")        }    }}

Main.go