learngo/interfaces/10-stringer/list.go

// For more tutorials: https://blog.learngoprogramming.com
//
// Copyright © 2018 Inanc Gumus
// Learn Go Programming Course
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
//

package main

import (
	"strings"
)

type list []*product

func (l list) String() string {
	if len(l) == 0 {
		return "Sorry. We're waiting for delivery 🚚.\n"
	}

	var str strings.Builder
	for _, p := range l {
		// fmt.Printf("* %s\n", p)
		str.WriteString("* ")
		str.WriteString(p.String())
		str.WriteRune('\n')
	}
	return str.String()
}

func (l list) discount(ratio float64) {
	for _, p := range l {
		p.discount(ratio)
	}
}