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GO速成篇

2024.11.247views

基础语法

变量

	var a int = 1
	var b int
	c := 3 // 只能用在函数内部，无法定义全局变量
	var d = 4
	fmt.Println(a, b, c, d)

const & iota

	const length int = 10
	const (
		BEIJING = iota
		SHANGHAI
		SHENZHEN
	)
	fmt.Println(BEIJING, SHANGHAI, SHENZHEN)


	const (
		a, b = iota + 1, iota + 2 // iota = 0,  a = 1, b = 2
		c, d                      // iota = 1,  c = 2, d = 3
		e, f                      // iota = 2,  e = 3, f = 4


		g, h = iota * 2, iota * 3 // iota = 3,  g = 6, h = 9
		i, j                      // iota = 4,  i = 8, j = 12
	)

func

func fool(a int, b int) int {
	return a + b
}


func Fool(a int, b int) int {
	return a + b
}


func fool3(a string, b int) (r1 int, r2 int) {
	r1 = 2000
	r2 = 3000
	return
}


func fool4(a int, b int) (r1, r2 int, r3 string) {
	r1 = a + b
	r2 = a - b
	r3 = "hello"
	return
}


func main() {
	foox := func() {
		fmt.Println("foo2")
	}
	fool(d, e)
	foox()
}

import

import (
    . "./lib2"
    _ "./lib3"
    lib4 "./libFourTooLongLibName"
)

指针

package main


import (
	"fmt"
)


func changeValue(a *int) {
	*a = 100
}


func main() {
	a := 10
	changeValue(&a)
	fmt.Println("a = ", a)
}

&a相当于获取a的地址。

a *int在内存中存储的是a的地址，非变量值，相当于a = &a。

*a = 100相当于找到a存储的内存地址其对应的内存地址，将其赋值100, *a就是一个指针，有指向另一个的作用。