inner_type.go

package main

import (
	"fmt"
)

/**
  complex使用场景?
*/

/*
值类型:

	bool
	int(32 or 64), int8, int16, int32, int64
	uint(32 or 64), uint8(byte), uint16, uint32, uint64
	float32, float64
	string
	complex64, complex128
	array    -- 固定长度的数组
*/

/**
  引用类型
    slice   -- 序列数组(最常用)
    map     -- 映射
    chan    -- 管道
*/

func innerType() {

	fmt.Println("=====内置类型=====")

	//bool
	var flagApp = false
	flag := true
	fmt.Println(flag)
	fmt.Println(flagApp)

	//int
	var a = 42 // utils := 42
	fmt.Println(a)

	//int8 表示范围: -128 ~ 127
	var int8 int8 = -127
	fmt.Println(int8)

	//int16
	var int16 int16 = -32768
	fmt.Println(int16)

	//int32
	var int32 int32 = -2147483648
	fmt.Println(int32)

	//int64
	var int64 int64 = -9223372036854775808
	fmt.Println(int64)

	//uint无符号整数
	var uint uint = uint(32767)
	fmt.Println(uint)

	//uint 等同于byte
	var _int8 uint8 = uint8(32)
	fmt.Println(_int8)

	//uint16
	var uint16 uint16 = 32767
	fmt.Println(uint16)

	//uint32
	var uint32 uint32 = 32767
	fmt.Println(uint32)

	//uint64
	var uint64 uint64 = 9223372036854775807
	fmt.Println(uint64)

	//float32
	var float32 float32 = 3.1415926
	fmt.Println(float32)

	//float64
	var float64 float64 = 3.1415926
	fmt.Println(float64)

	//string
	var str = "hello world"
	fmt.Println(str)

	//complex64
	var complex64 complex64 = 1 + 2i
	fmt.Println(imag(complex64))

	//complex128
	var complex128 complex128 = 1 + 2i
	fmt.Println(complex128)

	//array 数组
	arr := [3]int{1, 2, 3}
	for i := 0; i < len(arr); i++ { //访问数组方式1
		fmt.Println(arr[i])
	}

	for index, v := range arr { //访问数组方式2
		fmt.Println(index, v)
	}

	arr_index := [5]int{0: 1, 2, 3, 4} //下标初始化
	fmt.Println(arr_index)

	arr_dync := [...]int{1, 2, 3, 4} // 动态数组
	fmt.Println(arr_dync)

	array_struct := [...]struct { //数组对象
		name string
		age  uint8
	}{
		{"user1", 10}, // 可省略元素类型
		{"user2", 20}, // 别忘了最后一行的逗号
	}
	fmt.Println(array_struct)

	var arr0 = [3][2]int{{1, 2}, {3, 4}, {1, 2}} //多维数组
	fmt.Println(arr0)

	var arr1 [2][3]int = [...][3]int{{1, 2, 3}, {7, 8, 9}}
	fmt.Println(arr1)

	arr_5 := [5]int{1, 2, 7}
	findTargetNumArrIndex(arr_5, 8)
	sumArr(arr_5)    //求和
	printArr(&arr_5) //打印数组
	fmt.Println("arr_5: ", arr_5)

	//slice 切片
	slice := []int{1, 2, 3}
	ints := append(slice, 4)
	fmt.Println(ints)

	var aa = []int{1, 3, 4, 5, 6}
	fmt.Printf("slice a : %v , len(a) : %v cap(a):%v \n", aa, len(aa), cap(aa))
	bb := aa[2:3]
	fmt.Printf("slice b : %v , len(b) : %v cap(b):%v \n", bb, len(bb), cap(bb))
	cc := bb[0:3]
	fmt.Printf("slice c : %v , len(b) : %v cap(c):%v \n", cc, len(cc), cap(cc))

	//map
	m := make(map[string]string, 2)
	m["key"] = "val"
	fmt.Println(m["key"])

	userInfo := map[string]string{
		"k1": "v1",
		"k2": "v2",
	}
	fmt.Println(userInfo)

	val, ok := userInfo["k1"]
	if ok {
		fmt.Println(val)
	}

	for k, v := range userInfo { //遍历map
		fmt.Printf("k:%v  v:%v ", k, v)
	}

	//channel
	ch := make(chan string)
	go func() {
		ch <- "Hello from goroutine"
	}()
	msg := <-ch
	fmt.Println(msg)

	//错误类型
	getError()

}

func printArr(arr *[5]int) {
	fmt.Println("print array ")
	arr[0] = 10
	for i, v := range arr {
		fmt.Println(i, v)
	}
}

func sumArr(sourceArr [5]int) {
	sum := 0
	for i := range sourceArr {
		sum += sourceArr[i]
	}

	fmt.Println("sum值:", sum)
}

func findTargetNumArrIndex(sr [5]int, targetNum int) {

	for i, v := range sr {
		targetOtherNum := targetNum - v

		for j, tv := range sr {
			if tv == targetOtherNum {
				fmt.Println("组合下标:", i, j)
			}
		}
	}
}