Refactor input.dat and implement file writing in main.go; add readcsv.go for CSV file handling and gob serialization in gob/main.go

Author: s1thu

Reading_writing/challenge_readcsv/readcsv.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+)
+
+type Book struct {
+	title    string
+	price    float64
+	quantity int
+}
+
+func main() {
+	bks := make([]Book, 1)
+	file, err := os.Open("products.txt")
+	if err != nil {
+		log.Fatalf("Error %s opening file products.txt: ", err)
+	}
+	defer file.Close()
+
+	reader := bufio.NewReader(file)
+	for {
+		// read one line from the file:
+		line, err := reader.ReadString('\n')
+		if err == io.EOF {
+			break
+		}
+		// remove \r and \n so 2 in Windows, in Linux only \n, so 1:
+		line = string(line[:len(line)-2])
+		//fmt.Printf("The input was: -%s-", line)
+
+		strSl := strings.Split(line, ";")
+		book := new(Book)
+		book.title = strSl[0]
+		book.price, err = strconv.ParseFloat(strSl[1], 32)
+		if err != nil {
+			fmt.Printf("Error in file: %v", err)
+		}
+		//fmt.Printf("The quan was:-%s-", strSl[2])
+		book.quantity, err = strconv.Atoi(strSl[2])
+		if err != nil {
+			fmt.Printf("Error in file: %v", err)
+		}
+		if bks[0].title == "" {
+			bks[0] = *book
+		} else {
+			bks = append(bks, *book)
+		}
+	}
+	fmt.Println("We have read the following books from the file: ")
+	for _, bk := range bks {
+		fmt.Println(bk)
+	}
+}

Reading_writing/gob/main.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"bytes"
+	"encoding/gob"
+	"fmt"
+)
+
+// Define a sample struct
+type User struct {
+	Name string
+	Age  int
+}
+
+func main() {
+	// Original data
+	original := User{Name: "Alice", Age: 30}
+
+	// Create a buffer to hold the encoded data
+	var buf bytes.Buffer
+
+	// Create a gob encoder writing to the buffer
+	enc := gob.NewEncoder(&buf)
+
+	// Encode the struct into the buffer
+	err := enc.Encode(original)
+	if err != nil {
+		fmt.Println("Encoding failed:", err)
+		return
+	}
+
+	fmt.Println("✅ Serialized data into buffer.")
+
+	// Create a decoder reading from the same buffer
+	dec := gob.NewDecoder(&buf)
+
+	// Create a variable to hold the decoded data
+	var decoded User
+
+	// Decode into it
+	err = dec.Decode(&decoded)
+	if err != nil {
+		fmt.Println("Decoding failed:", err)
+		return
+	}
+
+	fmt.Println("✅ Decoded data from buffer:")
+	fmt.Println("Name:", decoded.Name)
+	fmt.Println("Age:", decoded.Age)
+}

Reading_writing/input.dat

@@ -1,4 +1,4 @@
-Hello sithu win
-win sithu sithu
+hello, world in a file
+hu sithu
 my name hello
 myat su yin

Reading_writing/main.go

@@ -52,6 +52,13 @@ func main() {
 	fmt.Println(col2)
 	fmt.Println(col3)
 
+	//writing into files
+	os.Stdout.WriteString("hello, world\n")
+	f, _ := os.OpenFile("input.dat", os.O_CREATE|os.O_WRONLY, 0)
+	defer f.Close()
+
+	f.WriteString("hello, world in a file\n")
+
 	for {
 		inputString, readerError := inputReader.ReadString('\n')
 		if readerError == io.EOF {