日期：2015年12月11日

以下摘自The Go Programming Language：

The import declarations must follow the package declaration.After that, a program consists of the declarations of functions, variables, constants, and types (introduced by the key words func, var , const , and type ); for the most part, the order of declarations does not matter.

import语句必须跟在package定义后面。请看下例：

package main

var str string = "Hello world!\n"

import "fmt"

func main(){
    // your code goes 
    fmt.Println(str)
}

编译如下：

./prog.go:5: syntax error: unexpected import

调整一下语句位置：

package main

import "fmt"

var str string = "Hello world!\n"

func main(){
    // your code goes 
    fmt.Println(str)
}

编译执行成功：

Hello world!

以下摘自The Go Programming Language：

Package main is special. It defines a standalone executable program, not a library. Within package main the function main is also special—it’s where execution of the program begins. Whatever main does is what the program does.

main package不同于其它library package，它定义了一个可执行程序。其中的main函数即是可执行文件的入口函数。