Max and min integer values in Golang

Today I needed to use the maximum unsigned 64-bit integer value possible in Golang.

Here is a short program I wrote with some help from Stack Overflow to help me remember how to calculate these without any dependencies.

package main

import "fmt"

const (
    minUint32 = uint32(0)
    maxUint32 = ^uint32(0)

    minUint64 = uint64(0)
    maxUint64 = ^uint64(0)

    minInt32 = int32(-maxInt32 - 1)
    maxInt32 = int32(maxUint32 >> 1)

    minInt64 = int64(-maxInt64 - 1)
    maxInt64 = int64(maxUint64 >> 1)
)

func details[numeric int32 | int64 | uint32 | uint64](name string, num numeric) {
    fmt.Printf("%9s -> dec: %21d\tbin: %65b\n", name, num, num)
}

func main() {
    details("minUint32", minUint32)
    details("maxUint32", maxUint32)

    details("minUint64", minUint64)
    details("maxUint64", maxUint64)

    details("minInt32", minInt32)
    details("maxInt32", maxInt32)

    details("minInt64", minInt64)
    details("maxInt64", maxInt64)
}

Running that shows:

minUint32 -> dec:                     0 bin:                                                                 0
maxUint32 -> dec:            4294967295 bin:                                  11111111111111111111111111111111
minUint64 -> dec:                     0 bin:                                                                 0
maxUint64 -> dec:  18446744073709551615 bin:  1111111111111111111111111111111111111111111111111111111111111111
 minInt32 -> dec:           -2147483648 bin:                                 -10000000000000000000000000000000
 maxInt32 -> dec:            2147483647 bin:                                   1111111111111111111111111111111
 minInt64 -> dec:  -9223372036854775808 bin: -1000000000000000000000000000000000000000000000000000000000000000
 maxInt64 -> dec:   9223372036854775807 bin:   111111111111111111111111111111111111111111111111111111111111111

It turns out these are constants in the math package.