package main

import (
	"bufio"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"strconv"
)

func PrintToTerminal() { //向目录下写文字
	file, err := os.OpenFile("/home/hu/go/src/hello.txt", os.O_CREATE|os.O_WRONLY, 0664)
	defer file.Close()
	if err != nil {
		fmt.Println("open file err,:", err)
		return
	}
	fmt.Fprintf(file, "do balance err\n")
}

type Student struct {
	Name  string
	Age   int
	Score float32
}

func (p *Student) String() string {
	var score string = fmt.Sprintf("%f", p.Score)
	return p.Name + " " + strconv.Itoa(p.Age) + " " + score
}
func fmtFmt() {
	var str = "stu01 18 91.55"
	var stu Student
	fmt.Sscanf(str, "%s %d %f", &stu.Name, &stu.Age, &stu.Score)
	fmt.Println(&stu)
}

var inputReader *bufio.Reader
var input string
var err error

func bufioBufio() { //read file by terminal
	inputReader := bufio.NewReader(os.Stdin)
	fmt.Println("Please enter some input:")
	input, err := inputReader.ReadString('\n') //单引号是比特，双引号是字符串
	if err != nil {
		fmt.Printf("read string failed:%s\n", input)
	}
	fmt.Printf("read file success,return :%s", input)

}
func readFile() {
	file, err := os.Open("/home/hu/go/src/hello.txt")
	defer file.Close()
	if err != nil {
		fmt.Println("read file err\n", err)
		return
	}

	inputReader := bufio.NewReader(file)
	// fmt.Println("Please enter some input:")
	input, err := inputReader.ReadString('\n') //单引号是比特，双引号是字符串
	if err != nil {
		fmt.Printf("read string failed:%s\n", input)
	}
	fmt.Printf("read file success,return :%s", input)

}

type CharCount struct {
	ChCount    int
	NUmCount   int
	SpaceCount int
	OtherCount int
}

func countInput() {
	file, err := os.Open("/home/hu/go/src/hello.txt")
	defer file.Close()
	if err != nil {
		fmt.Printf("read file err:%s\n", err)
		return
	}
	var count CharCount
	reader := bufio.NewReader(file)
	for {
		str, err := reader.ReadString('\n')
		if err == io.EOF {
			break
		}
		if err != nil {
			fmt.Printf("read string failed,err:%s\n", err)
		}
		runeArr := []rune(str)
		for _, v := range runeArr {
			switch {
			case v >= 'a' && v <= 'z':
				fallthrough
			case v >= 'A' && v <= 'Z':
				count.ChCount++
			case v >= '0' && v <= '9':
				count.NUmCount++
			case v == ' ':
				count.SpaceCount++
			default:
				count.OtherCount++
			}
		}
	}
	fmt.Printf("charCount is %d\n", count.ChCount)
	fmt.Printf("NumCount is %d\n", count.NUmCount)
	fmt.Printf("SpaceCount is %d\n", count.SpaceCount)
	fmt.Printf("OtherCount is %d\n", count.OtherCount)
}
func testioutil() {
	inputFile := "/home/hu/go/src/hello.txt"
	outputFile := "/home/hu/go/src/world.txt"
	buf, err := ioutil.ReadFile(inputFile)
	if err != nil {
		fmt.Fprintf(os.Stderr, "File Error:%s\n", err)
		return
	}
	fmt.Printf("%s\n", string(buf))
	err = ioutil.WriteFile(outputFile, buf, 0x64)
	if err != nil {
		panic(err.Error())
	}
}
func main() {
	// PrintToTerminal()

	// fmtFmt()

	// bufioBufio()

	// readFile()

	// countInput()

	testioutil()
}