go的array

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package main

import (
	"fmt"
)

func testArray1() {
	var a [5]int
	fmt.Println(a)
	a[0] = 200
	a[1] = 300
	fmt.Println(a)
}

func testArray3() {
	//var a [5]int = [5]int{1, 2, 3, 4, 5}
	//a := [5]int{1, 2, 3, 4, 5}  // 也可以这样写
	a := [...]int{1, 2, 3, 4, 5}   // 也可以这样写
	fmt.Println(a)
	a[0] = 200
	a[1] = 300
	fmt.Println(a)
	fmt.Printf("这是a:%v\n",a)
	fmt.Printf("这是a2:%#v\n",a)
}

func testArray5() {
	//a := [5]int{1, 2, 3}
	a := [5]int{3: 100, 4: 200} // 也可以这样写
	fmt.Println(a)
	a[0] = 200
	a[1] = 300
	fmt.Println(a)
}

func testArray7() {
	a := [5]int{3: 100, 4: 200}
	fmt.Println(a)
	a[0] = 200
	a[1] = 300
	fmt.Println(a)
	fmt.Printf("len(a)=%d\n", len(a))

/*	var  b [3]int
	b = a  // 报错  不同长度类型不能赋值   cannot use a (type [5]int) as type [3]int in assignment
	fmt.Println(b)*/

	var b [5]int
	b = a
	fmt.Println(b)
}


func testArray9() {
	a := [5]int{3: 100, 4: 200}
	fmt.Println(a)
	var index,value int
	for index,value = range a{
		fmt.Printf("循环a[%d]=%d\n",index,value)
	}

	// 直接赋值
	for index, value := range a {
		fmt.Printf("a[%d]=%d\n", index, value)
	}
	// 不想要下标,就把下标忽略掉
	for _, value := range a {
		fmt.Printf("%d\n", value)
	}
}

func testArray11() {
	var a [3][2]int
	a[0][0] = 10
	a[0][1] = 28
	a[1][0] = 30
	a[1][1] = 32
	a[2][0] = 35
	a[2][1] = 38

	fmt.Println(a)
	for i := 0; i < 3; i++ {
		for j := 0; j < 2; j++ {
			fmt.Printf("%d  ", a[i][j])
		}
		fmt.Println()
	}

	for i, val := range a {
		fmt.Printf("row[%d]=%v\n", i, val)
		for j, val2 := range val {
			fmt.Printf("(%d,%d)=%d\n", i, j, val2)
		}
		fmt.Println()
	}
}

func testArray12() {
	a := [3]int{10, 20, 30}
	fmt.Println(a)
	b := a // 数组赋值是值类型,改变b中的不影响
	b[0] = 100
	a[1] = 1000
	fmt.Printf("a=%v,b=%v\n", a, b)
}

func testArray13() {
	var a int = 100
	fmt.Println(a)
	b := a
	fmt.Printf("未修改a=%v,b=%v\n", a, b)
	b = 1000
	fmt.Printf("a=%v,b=%v\n", a, b)
}

func modify(b [3]int) {
	b[0] = 120
}
func testArray14() {
	var a [3]int = [3]int{10, 20, 30}
	modify(a)
	fmt.Println(a)
}

func main() {
	//testArray1()
	//testArray3()
	//testArray5()
	//testArray7()
	//testArray9()
	testArray11()
	testArray12()
	testArray13()
	testArray14()
}