40 lines
831 B
Go
40 lines
831 B
Go
// 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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// For more tutorials : https://learngoprogramming.com
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// In-person training : https://www.linkedin.com/in/inancgumus/
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// Follow me on twitter: https://twitter.com/inancgumus
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package main
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import (
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"fmt"
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"math/rand"
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)
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// PowerDrawer represents an electrical device that can draw power.
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// The power source doesn't have to be a Socket.
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type PowerDrawer interface {
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Draw(power int)
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}
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// Socket has the power!
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type Socket struct {
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power int
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}
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// Plug a device to draw power from the `Socket`
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func (s *Socket) Plug(device PowerDrawer) error {
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n := rand.Intn(50) + 1
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if s.power-n < 0 {
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return fmt.Errorf("socket is out of power for %dkW", n)
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}
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s.power -= n
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device.Draw(n)
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return nil
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}
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