Solution to https://tour.golang.org/methods/23

exercise-rot-reader.go

package main

import (
	//"fmt"
	"io"
	"os"
	"strings"
)

type rot13Reader struct {
	r io.Reader
}

func (r *rot13Reader) Read(b []byte) (n int, err error) {
	n, err = r.r.Read(b)
	for i := range b[:n] {
		//fmt.Printf("b = %v\n", b)
		if b[i] == 32 {
		
		} else if b[i] < 78 || b[i] < 110 {
			b[i] = b[i] + 13

		} else if b[i] > 78 || b[i] > 110 {
			b[i] = b[i] - 13
		}
	}
	return
}

func main() {
	s := strings.NewReader("Lbh penpxrq gur pbqr!")
	r := rot13Reader{s}
	io.Copy(os.Stdout, &r)
}