103 lines
2.8 KiB
Go
103 lines
2.8 KiB
Go
// 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 "fmt"
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func main() {
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var (
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myAge byte
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herAge byte
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// this declares an array with two byte elements
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// its length : 2
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// its element type: byte
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ages [2]byte
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// this declares an array with five string elements
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// its length : 5
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// its element type: string
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tags [5]string
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// this array doesn't occupy any memory space (its length is zero)
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// its length : 0
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// its element type: byte
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zero [0]byte
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// this array uses a constant expression
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// its length : 3
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// its element type: byte
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agesExp [2 + 1]byte
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// uncomment the code below and observe the error
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//
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// wrongDeclaration [-1]byte
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)
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fmt.Printf("myAge : %d\n", myAge)
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fmt.Printf("herAge : %d\n", herAge)
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// Since arrays we've declared here don't have any elements,
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// Go automatically sets all their elements to their zero values
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// depending on their element type.
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// #v verb prints the array's length, element type and its elements
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fmt.Printf("ages : %#v\n", ages)
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fmt.Printf("tags : %#v\n", tags)
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fmt.Printf("zero : %#v\n", zero)
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fmt.Printf("agesExp : %#v\n", agesExp)
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// note:
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// ages and agesExp get printed 0x0 because they're byte arrays.
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// bytes are represented with hex values. 0x0 means 0.
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// =========================================================================
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// GETTING AND SETTING ARRAY ELEMENTS
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// =========================================================================
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// Note:
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//
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// Since, I've already declared the ages variable above,
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// and, to show you the example below, I needed to create a new block.
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//
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// ages variable below is in a new block below. So, it's a new variable.
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//
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// I did so because I need to change the element type of the ages array
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// to int (or, subtracting from a byte results in wraparound).
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{
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var ages [2]int
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fmt.Println()
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fmt.Printf("ages : %#v\n", ages)
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fmt.Printf("ages's type : %T\n", ages)
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fmt.Println("len(ages) :", len(ages))
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fmt.Println("ages[0] :", ages[0])
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fmt.Println("ages[1] :", ages[1])
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fmt.Println("ages[len(ages)-1] :", ages[len(ages)-1])
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// WRONG:
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// fmt.Println("ages[-1] :", ages[-1])
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// fmt.Println("ages[2] :", ages[2])
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// fmt.Println("ages[len(ages)] :", ages[len(ages)])
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ages[0] = 6
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ages[1] -= 3
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// WRONG:
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// ages[0] = "Can I?"
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fmt.Println("ages[0] :", ages[0])
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fmt.Println("ages[1] :", ages[1])
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ages[0] *= ages[1]
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fmt.Println("ages[0] :", ages[0])
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fmt.Println("ages[1] :", ages[1])
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}
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}
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