Facebook: Rotational Cipher

Rotational_Cipher.go

package main

import (
  "fmt"
)


func rotationalCipher(input string, rotationFactor int) string {
	b := []uint8(input)
	for i:=0; i < len(input); i++ {
		switch {
			case 'a' <= b[i] && b[i] <= 'z': {
				b[i] += uint8(rotationFactor)
				for b[i] > 'z' {
					b[i] = b[i] - 'z' + 'a' - 1
				}
			}
			case 'A' <= b[i] && b[i] <= 'Z': {
				b[i] += uint8(rotationFactor)
				for b[i] > 'Z' {
					b[i] = b[i] - 'Z' + 'A' - 1
				}
			}
			case '0' <= b[i] && b[i] <= '9': {
				b[i] += uint8(rotationFactor)
				for b[i] > '9' {
					b[i] = b[i] - '9' + '0' - 1
				}
			}
		}
	}

	return string(b)
}

func main() {
  testDatas := []struct{
		input string
		rotationFactor int
		result string
	} {
		{
			"Zebra-493?",
			3,
			"Cheud-726?",
		},
		{
			"abcdefghijklmNOPQRSTUVWXYZ0123456789",
			39,
			"nopqrstuvwxyzABCDEFGHIJKLM9012345678",
		},
    {
      "1234567890-=!@#$%^&*()_+{}[]||\\<>:;'?/~`,.",
      89765,
      "6789012345-=!@#$%^&*()_+{}[]||\\<>:;'?/~`,.",
    },
    {
      "1234567890-=!@#$%^&*()_+{}[]||\\<>:;'?/~`,.Zebra-493?",
      3,
      "4567890123-=!@#$%^&*()_+{}[]||\\<>:;'?/~`,.Cheud-726?",
    },
	}

	for _, td := range testDatas {
		r := rotationalCipher(td.input, td.rotationFactor)
		if r != td.result {
      fmt.Printf("Failed: Source: %v ==> %d\n Expected:%v \n Actual:  %v\n",
				td.input,
				td.rotationFactor,
				td.result,
				r)
		} else {
      fmt.Printf("Passed: Source: %v ==> %d\n",
				td.input,
				td.rotationFactor)
    }
  } 
}