mathtools/cmd/sqrtRepetend.go

/*
Copyright © 2025 filifa

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package cmd

import (
	"fmt"
	"log"
	"math/big"

	"github.com/spf13/cobra"
	"scm.dairydemon.net/filifa/mathtools/internal/lib"
)

func sqrtRepetend(cmd *cobra.Command, args []string) {
	x := new(big.Int)

	for _, s := range args {
		_, ok := x.SetString(s, 10)
		if !ok {
			log.Print("invalid input " + s)
			continue
		}

		repetend, err := lib.SqrtRepetend(x)
		if err != nil {
			log.Print(s + " is a perfect square")
			continue
		}

		fmt.Print(repetend[0])
		for _, r := range repetend[1:] {
			fmt.Printf(" %s", r)
		}
		fmt.Println()
	}
}

// sqrtRepetendCmd represents the sqrtRepetend command
var sqrtRepetendCmd = &cobra.Command{
	Use:   "sqrt-repetend N [N ...]",
	Short: "Compute the repetend of the continued fraction of square roots",
	Long: `Compute the repetend of the continued fraction of the square root of the input.

For each argument n, this will output the repetend of the continued fraction of sqrt(n). For example,
mathtools sqrt-repetend 12 15 19
will output
2 6
1 6
2 1 3 1 2 8`,
	Args: cobra.MinimumNArgs(1),
	Run:  sqrtRepetend,
}

func init() {
	rootCmd.AddCommand(sqrtRepetendCmd)

	// Here you will define your flags and configuration settings.

	// Cobra supports Persistent Flags which will work for this command
	// and all subcommands, e.g.:
	// sqrtRepetendCmd.PersistentFlags().String("foo", "", "A help for foo")

	// Cobra supports local flags which will only run when this command
	// is called directly, e.g.:
	// sqrtRepetendCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
}