51 lines
940 B
Go
51 lines
940 B
Go
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// For more tutorials: https://blog.learngoprogramming.com
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//
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// Copyright © 2018 Inanc Gumus
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// Learn Go Programming Course
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// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
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//
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package main
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import (
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"fmt"
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"strconv"
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"time"
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)
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type book struct {
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product
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published interface{}
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}
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// book satisfies the fmt.Stringer
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func (b *book) String() string {
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p := format(b.published)
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// product.String has a pointer receiver.
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// that's why we need to take its address here.
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//
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// when you put a value in an interface, the interface
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// cannot run that value's type's value-receiver methods.
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return fmt.Sprintf("%s - (%v)", &b.product, p)
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}
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func format(v interface{}) string {
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var t int
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switch v := v.(type) {
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case int:
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t = v
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case string:
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t, _ = strconv.Atoi(v)
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default:
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return "unknown"
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}
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// Mon Jan 2 15:04:05 -0700 MST 2006
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const layout = "2006/01"
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u := time.Unix(int64(t), 0)
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return u.Format(layout)
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}
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