basic-data-type-sizes.go

package main

import (
	"fmt"
	"os"
	"sort"
	"text/tabwriter"
	"unsafe"
)

func main() {
	sizes := map[string]uintptr{
		"bool":       unsafe.Sizeof(true),
		"complex128": unsafe.Sizeof(complex128(0)),
		"complex64":  unsafe.Sizeof(complex64(0)),
		"float32":    unsafe.Sizeof(float32(0)),
		"float64":    unsafe.Sizeof(float64(0)),
		"int16":      unsafe.Sizeof(int16(0)),
		"int32":      unsafe.Sizeof(int32(0)),
		"int64":      unsafe.Sizeof(int64(0)),
		"int8":       unsafe.Sizeof(int8(0)),
		"string":     unsafe.Sizeof(""),
		"uint16":     unsafe.Sizeof(uint16(0)),
		"uint32":     unsafe.Sizeof(uint32(0)),
		"uint64":     unsafe.Sizeof(uint64(0)),
		"uint8":      unsafe.Sizeof(uint8(0)),
	}

	keys := make([]string, 0, len(sizes))
	for k := range sizes {
		keys = append(keys, k)
	}
	sort.Strings(keys)

	w := tabwriter.NewWriter(os.Stdout, 1, 1, 1, ' ', 0)
	fmt.Fprintln(w, "|", "data type", "\t|", "size (bytes)", "\t|")
	fmt.Fprintln(w, "|", "---", "\t|", "---", "\t|")
	for _, k := range keys {
		if v, ok := sizes[k]; ok {
			fmt.Fprintln(w, "|", k, "\t|", v, "\t|")
		}
	}
	w.Flush()
}