Input/Output examples

input_output.go

package main

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

func main() {
	// Read file with .Read()
	f, err := os.OpenFile("a.txt", os.O_RDONLY, 0)
	if err != nil {
		panic(err)
	}
	stat, _ := f.Stat()
	b := make([]byte, stat.Size())
	n, err := f.Read(b)
	if err != nil {
		panic(err)
	}
	fmt.Println("Readed ", n, " bytes")
	fmt.Println(string(b))

	//Read by byte
	f, err = os.OpenFile("a.txt", os.O_RDONLY, 0)
	if err != nil {
		panic(err)
	}
	fileContent := make([]byte, 0)
	b = make([]byte, 1)
	_, err = f.Read(b)
	if err != nil {
		panic(err.Error())
	}
	for err == nil {
		fileContent = append(fileContent, b[0])
		_, err = f.Read(b)
	}
	fmt.Println(string(fileContent))

	//Read file with ReadAll
	f, err = os.OpenFile("a.txt", os.O_RDONLY, 0)
	if err != nil {
		panic(err)
	}
	content, err := ioutil.ReadAll(f)
	if err != nil {
		panic(err)
	}
	fmt.Println(string(content))

	// Read file
	//content, err := ioutil.ReadFile("a.txt")

	// Read one line from keyboard
	reader := bufio.NewReader(os.Stdin)
	s, _ := reader.ReadString('\n')
	fmt.Println(s)

	
	// Read two ints from file
	f, err = os.Open("b.txt")
	if err != nil {
		panic(err)
	}
	var x, y int
	fmt.Fscanln(f, &x, &y)
	fmt.Println(x + y)

}