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View Code? Open in Web Editor NEW「Go语言学习指南」一份涵盖大部分 Golang 程序员所需要掌握的核心知识,拥有 Go语言教程、Go开源书籍、Go语言入门教程、Go语言学习路线。零基础学习 Go语言、Go编程,首选 GoGuide。
「Go语言学习指南」一份涵盖大部分 Golang 程序员所需要掌握的核心知识,拥有 Go语言教程、Go开源书籍、Go语言入门教程、Go语言学习路线。零基础学习 Go语言、Go编程,首选 GoGuide。
os包和flag包获取命令行参数对比
通过os包获取命令行参数
如果用户没有传递参数会报错
需要严格按照代码中的顺序传递参数, 否则会造成数据混乱
不能指定参数的名称
获取到的数据都是字符串类型
这里的 int main() 要换成 func main() 不然编译通不过
package main
import (
"os"
"fmt"
)
// 下面这个 int main( )要换成 func main ( ) ************************************
int main(){
name := os.Args[1]
age := os.Args[2]
fmt.Println("name = ", name)
fmt.Println("age = ", age)
}
数值类型转字符串类型strconv..FormatXxx()中的 str3 := strconv.FormatFloat(num5, 'f', -1, 64)应该是 str3 := strconv.FormatFloat(num5, 'f', -1, 32)
操作符^=和|=的含义写反了
GO语言有值类型、引用类型
但是参数传递只有 值传递
引用类型传递的其相应的指针,参数的内存是独立的,拷贝过来的指针地址。
关于这点【不能将函数内的指向局部变量的指针作为返回值, 函数结束指向空间会被释放】有疑问,示例如下:
package main
import (
"fmt"
)
func f() *int {
n := 100
fmt.Println("1:", &n, n)
return &n
}
func main() {
n := f()
fmt.Println("2:", n, *n)
(*n) = 99
fmt.Println("3:", n, *n)
}
输出:
1: 0x140000aa008 100
2: 0x140000aa008 100
3: 0x140000aa008 99
package main
import "fmt"
func main() {
num := 1
if(num <= 10){
fmt.Println(num)
num++
goto outer // 死循环
}
outer:
fmt.Println("come here")
}
这仅仅是个if判断,也没有无限循环,且goto标记位于语句块之外的结尾处,即使循环也只执行一次,为什么要注释为死循环呢?
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