add: slice internals backing array and slice header

16-slices/08-slice-internals-1-backing-array/1-theory/main.go

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+// 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 s "github.com/inancgumus/prettyslice"
+
+func main() {
+	// ages, first and last2 have the same backing arrays
+	ages := []int{35, 15, 25}
+	first := ages[0:1]
+	last2 := ages[1:3]
+
+	ages[0] = 55
+	ages[1] = 10
+	ages[2] = 20
+
+	// grades and ages have separate backing arrays
+	grades := []int{70, 99}
+	grades[0] = 50
+
+	s.Show("ages", ages)
+	s.Show("ages[0:1]", first)
+	s.Show("ages[1:3]", last2)
+	s.Show("grades", grades)
+
+	// let's create a new scope
+	// 'cause i'm going to use variables with the same name
+	{
+		// ages and agesArray have the same backing arrays
+		agesArray := [3]int{35, 15, 25}
+		ages := agesArray[0:3]
+
+		ages[0] = 100
+		ages[2] = 50
+
+		s.Show("agesArray", agesArray[:])
+		s.Show("agesArray's ages", ages)
+	}
+}

16-slices/08-slice-internals-1-backing-array/2-example/main.go

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+// 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 (
+	s "github.com/inancgumus/prettyslice"
+)
+
+func main() {
+	// #1: arrays and non-empty slice literals create an array.
+	// For the arrays, it's explicit, but for the slices,
+	// it's done implicitly, behind the scenes.
+
+	grades := [...]float64{40, 10, 20, 50, 60, 70} // #1
+	// grades := []float64{40, 10, 20, 50, 60, 70} // #4
+
+	// #5: let's break the connection
+	// #6: comment-out
+	// var newGrades []float64
+	// newGrades = append(newGrades, grades...)
+
+	// #6: shortcut: []float64(nil) is a nil float64 slice
+	// newGrades := append([]float64(nil), grades...)
+
+	// #2: cheap: slicing doesn't allocate new memory (array).
+	// front := grades[:3]
+
+	// front := newGrades[:3] // #5
+
+	// #3: sort its first segment
+	// sort.Float64s(front)
+
+	// #7: new slices look at the same backing array
+	// front, front2, front3, newGrades, they all have the same backing array
+	// front2 := front[:3]
+	// front3 := front
+
+	s.PrintBacking = true       // #1
+	s.MaxPerLine = 7            // #1
+	s.Show("grades", grades[:]) // #1
+	// s.Show("newGrades", newGrades) // #5
+	// s.Show("front", front)         // #2
+	// s.Show("front2", front2)       // #7
+	// s.Show("front3", front3)       // #7
+}