HappyNumbers

happy_numbers.go

package main

import (
        "fmt"
)

func is_happy_number(number int) bool {
        if number < 10 {
                return (number == 1 || number == 7)
        } else {
                sum := 0
                for ; number != 0; number /= 10 {
                        digit := number % 10
                        sum += digit * digit
                }
                return is_happy_number(sum)
        }
}

func main() {
        for n := 1; n <= 1000; n += 1 {
                if is_happy_number(n) {
                        fmt.Printf("%d, ", n)
                }
        }
}