[go ~ 0 to 1] on the first day, June 24, variables, conditional judgment cycle statement

1. How variables are declared

Standard statement

var  Variable name   data type  =  A variable's value 

A short statement

 Variable name  :=  A variable's value 

2. if conditional

1.if conditional

	// conditional :
	var flag = true

	if flag {
    
		fmt.Println(" The result is true")
	} else {
    
		fmt.Println(" The result is false")
	}

2. Multi condition judgment

//  Multi condition judgment 
age := 30

if age == 20 {
    
    fmt.Println(" The age is just 20 year ")
} else if age > 20 {
    
    fmt.Println(" Older than 20 year ")
} else {
    
    fmt.Println(" Less than age 20 year ")
	}

3. Scope judgment

num The scope of is limited to if In the sentence

	// Scope judgment :
	if num := 20; num < 30 {
    
		fmt.Println("num Less than 30")
	} else {
    
		fmt.Println("num Greater than 30")
	}

3.for Loop statement

1. The basic format

for  Variable declarations ; conditional ; Step expression {
    
    Loop body statement 
}
for num := 0; num < 100; num++ {
    
    
    fmt.Printf(" from %d To 100\n", num)
    
	}

2. Dead cycle

for ;;{
    
     Loop body statement 
}
	for ; ; {
    
		fmt.Println(" I am a dead circle ")
	}

end. practice

Statistics in a text Numbers , Letter and The number of Chinese characters

package main

import (
	"bufio"
	"fmt"
	"io"
	"os"
	"unicode"
)

var (
	// Numbers   Letter   Chinese characters 
	num, wd, han = 0, 0, 0
)

func main() {
    

	// Open file 
	file, err := os.Open("D:\\ Exercise text .txt")
	if err != nil {
    
		fmt.Printf(" An error occurred while reading the file  %v\n", err.Error())
	}

	// Make sure to turn off io flow 
	defer file.Close()

	// Get character buffer stream 
	reader := bufio.NewReader(file)

	// Convert to string
	for {
    

		readString, err := reader.ReadString('\n')

		if err == io.EOF {
    
			// Description read complete 
			transition(readString)

			fmt.Println(" File read complete ")
			break
		}

		if err != nil {
    
			fmt.Printf(" Error reading character stream  %v\n", err)
		}

		transition(readString)

	}

	fmt.Println(" Number of numbers  : ", num, "  Number of letters  : ", wd, "  The number of Chinese characters  :", han)

}

func transition(readString string) {
    
	for a1, str := range readString {
    

		a1 = a1

		fmt.Println(str)

		if unicode.IsNumber(str) {
    

			num++
		}
		if unicode.IsLower(str) {
    

			wd++
		}
		if unicode.IsUpper(str) {
    

			wd++
		}
		if unicode.Is(unicode.Han, str) {
    

			han++
		}

	}

}