Files
learngo/16-slices/exercises/18-internals-slice-header/solution/main.go
2019-08-18 15:43:09 +03:00

62 lines
1.2 KiB
Go

// 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 (
"fmt"
"runtime"
"runtime/debug"
"unsafe"
)
const size = 1e7
func main() {
debug.SetGCPercent(-1)
report("initial memory usage")
var array [size]int
report("after declaring an array")
array2 := array
report("after copying the array")
passArray(array)
slice1 := array[:]
slice2 := array[1e3:]
slice3 := array[1e3:1e4]
report("after slicings")
passSlice(slice3)
fmt.Println()
fmt.Printf("Array's size : %d bytes.\n", unsafe.Sizeof(array))
fmt.Printf("Array2's size: %d bytes.\n", unsafe.Sizeof(array2))
fmt.Printf("Slice1's size: %d bytes.\n", unsafe.Sizeof(slice1))
fmt.Printf("Slice2's size: %d bytes.\n", unsafe.Sizeof(slice2))
fmt.Printf("Slice3's size: %d bytes.\n", unsafe.Sizeof(slice3))
}
func passArray(items [size]int) {
items[0] = 100
report("inside passArray")
}
func passSlice(items []int) {
report("inside passSlice")
}
func report(msg string) {
var m runtime.MemStats
runtime.ReadMemStats(&m)
fmt.Printf("[%s]\n", msg)
fmt.Printf("\t> Memory Usage: %v KB\n", m.Alloc/1024)
}