Learning go the fizzybuzzy way

0-fizzbuzz-simple.go

package main

// [Fizzbuzz: One Simple Interview Question](https://www.youtube.com/watch?v=QPZ0pIK_wsc)

import "fmt"

func fizzbuzz(i int) (text string) {
	fizz := i%3 == 0
	buzz := i%5 == 0

	if fizz && buzz {
		return "fizzbuzz"
	} else if fizz {
		return "fizz"
	} else if buzz {
		return "buzz"
	} else {
		return fmt.Sprintf("%d", i)
	}
}

func main() {
	for i := 0; i <= 35; i++ {
		fmt.Printf("%s\n", fizzbuzz(i))
	}
}

1-fizzbuzz-icky.go

package main

// [Fizzbuzz: One Simple Interview Question](https://www.youtube.com/watch?v=QPZ0pIK_wsc)

import "fmt"

func fizzbuzz(i int) (trigger bool, text string) {
	fizz := i%3 == 0
	buzz := i%5 == 0

	if fizz && buzz {
		text = "fizzbuzz"
	} else if fizz {
		text = "fizz"
	} else if buzz {
		text = "buzz"
	}

	return fizz || buzz, text
}

func main() {
	for i := 0; i <= 100; i++ {
		trigger, text := fizzbuzz(i) // :| can't be used as a value in if ... {}
		if trigger {
			fmt.Println(text)
		} else {
			fmt.Println(i)
		}
	}
}

2-fizzbuzz-typed.go

package main

import "fmt"

// [Fizzbuzz: One Simple Interview Question](https://www.youtube.com/watch?v=QPZ0pIK_wsc)

type FizzyBuzzy int

func (b FizzyBuzzy) String() (text string) {

	fizz := b%3 == 0
	buzz := b%5 == 0

	if buzz && fizz {
		return "fizzbuzz"
	} else if fizz {
		return "fizz"
	} else if buzz {
		return "buzz"
	} else {
		return fmt.Sprintf("%d", b)
	}
}

func main() {
	for i := 0; i <= 36; i++ {
		fmt.Printf("%v\n", FizzyBuzzy(i))
	}
}

3-fizzbuzz-interface-type.go

package main

// [Fizzbuzz: One Simple FizzyInterview Question](https://www.youtube.com/watch?v=QPZ0pIK_wsc)

import (
	"fmt"
)

type FizzyBuzzy interface {
	Analyze(v int)
	Value() int
	String() string // explicitly required
}

type EvenInt struct {
	value int
	repr  string
}

type FizzyInt struct {
	value int
	repr  string
	fizz  bool
	buzz  bool
}

// Analyze an even integer
func (i *EvenInt) Analyze(v int) {
	i.value = v
	i.repr = "even"
}

// Analyze a number and determine its fizzy/buzzy-ness
func (i *FizzyInt) Analyze(v int) {
	i.value = v

	i.fizz = i.value%3 == 0
	i.buzz = i.value%5 == 0

	if i.fizz && i.buzz {
		i.repr = "fizzbuzz"
	} else if i.fizz {
		i.repr = "fizz"
	} else if i.buzz {
		i.repr = "buzz"
	} else {
		// if we've ruled out even numbers
		// this number is then a candidate prime number?
		// due to the inadvertent Sieve of Eratosthenes
		// off course, doesn't catch the fizzy primes
		i.repr = "prime?"
	}
}

// candidate for generics?
func (fi EvenInt) String() (text string) {
	return fi.repr
}

// candidate for generics?
func (fi FizzyInt) String() (text string) {
	return fi.repr
}

// candidate for generics?
func (fi EvenInt) Value() int {
	return fi.value
}

// candidate for generics?
func (fi FizzyInt) Value() int {
	return fi.value
}

// interface method
func repr(fb FizzyBuzzy) (text string) {
	return fmt.Sprintf("%2d is %s", fb.Value(), fb.String())
}

func main() {
	for i := 0; i <= 36; i++ {
		var fb FizzyBuzzy
		if i%2 == 0 {
			fb = new(EvenInt)
		} else {
			fb = new(FizzyInt)
		}
		fb.Analyze(i)
		fmt.Printf("%v\n", repr(fb))
	}
}