package main

import (
	"fmt"
	"runtime"
)

func main() {
	//create an array with a lot of data
	massiveData := make([]int, 1_000_000)
	for i := range massiveData {
		massiveData[i] = i
	}

	// Task: Extract the first 8 elements safely

	//1. attempt: use the slice operator
	//smallSlice := massiveData[:8]
	// consequence -> smallSlice and massiveData point to the same underlying array.
	// Therefore, setting massiveData to nil is not sufficient to release that big array.

	//2. attempt: create a new slice (with a new underlying array) and copy data
	smallSlice := make([]int, 8)
	copy(smallSlice, massiveData[:8])

	massiveData = nil //don't use massive data anymore: Underlying array shall be freed.
	runtime.GC()      //run the garbage collector to make sure that all unused data is actually freed

	//cap(smallSlice) should be 8 or similar, but not close to 1_000_000. The majority of the data should have been released by now
	fmt.Printf("Small Slice: %v, Len: %d, Cap: %d\n", smallSlice, len(smallSlice), cap(smallSlice))
}