rot13Reader

exercise9.go

package main

import (
    "io"
    "os"
    "strings"
)

type rot13Reader struct {
    r io.Reader
}

func (rot *rot13Reader) Read(buf []byte) (n int, e error) {
    n, e = rot.r.Read(buf)
    for i:= 0; i < len(buf); i++ {
        c := buf[i]
        if (c >= 'A' && c <= 'N') || (c >= 'a' && c < 'n') {
            buf[i] += 13
        } else if (c >= 'M' && c <= 'Z') || (c >= 'm' && c <= 'z') {
            buf[i] -= 13
        }
    }
    return
}

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