A tour of Go: Exercise: rot13 Reader

A tour of Go Exercise: rot13 Reader

A common pattern is an IO. Reader that wraps anotherIo. Reader,
Modifying the stream in some way.

For example, the gzip. newreader function takesIo. Reader(
Stream of gzipped data) and returns* Gzip. ReaderThat also implementsIo. Reader(A stream of the decompressed data ).

ImplementRot13readerThat implementsIo. ReaderAnd reads fromIo. Reader,
Modifying the stream by applying the rot13 substitution cipher to all alphabetical characters.

TheRot13readerType is provided for you. Make itIo. ReaderBy implementing
ItsReadMethod

 package mainimport ("Io" "OS" "strings") type rot13reader struct {r Io. reader} func rot13 (P byte) byte {Switch {case P> = 'A' & P <= 'M ': P = p-'A' + 'n' case P> = 'n' & P <= 'Z ': P = p-'n' + 'A' case P> = 'A' & P <= 'M ': P = p-'A' + 'n' case P> = 'n' & P <= 'Z ': P = p-'n' + 'A'} return p} func (V rot13reader) read (P [] Byte) (N int, err error) {Original: = make ([] B Yte, 50) I, err: = v. r. read (original) for index, value: = range original [: I] {P [Index] = rot13 (value)} return I, err} func main () {s: = strings. newreader ("LBH penpxrq Gur pbqr! ") R: = rot13reader {s} io. Copy (OS. stdout, & R)}