Time and Formatting

Compare Times

Before, After, and Equal compare two deterministic time values.

compare time Comparing times answers ordering questions without relying on the current clock.

Compare Times

offsetHours
compare_times.go
Replay: real traced execution (multi-file project)
package main

import (
	"fmt"
	"time"
)

func main() {
	var offsetHours = 2
	deadline := time.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC)
	check := deadline.Add(time.Duration(offsetHours) * time.Hour)
	isBefore := check.Before(deadline)
	isAfter := check.After(deadline)

	fmt.Println("offsetHours=", offsetHours)
	fmt.Println("check=", check.Format("15:04"))
	fmt.Println("before=", isBefore)
	fmt.Println("after=", isAfter)
}

package main

import (
	"fmt"
	"time"
)

func main() {
	var offsetHours = -1
	deadline := time.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC)
	check := deadline.Add(time.Duration(offsetHours) * time.Hour)
	isBefore := check.Before(deadline)
	isAfter := check.After(deadline)

	fmt.Println("offsetHours=", offsetHours)
	fmt.Println("check=", check.Format("15:04"))
	fmt.Println("before=", isBefore)
	fmt.Println("after=", isAfter)
}

package main

import (
	"fmt"
	"time"
)

func main() {
	var offsetHours = 5
	deadline := time.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC)
	check := deadline.Add(time.Duration(offsetHours) * time.Hour)
	isBefore := check.Before(deadline)
	isAfter := check.After(deadline)

	fmt.Println("offsetHours=", offsetHours)
	fmt.Println("check=", check.Format("15:04"))
	fmt.Println("before=", isBefore)
	fmt.Println("after=", isAfter)
}

  1. offsetHours ← 2, deadline ← time.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC)

    8func main() {9  var offsetHours→ 2 = 2 //@offsetHours=-1, 510  deadline→ time.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC) := time.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC)11  check→ time.Date(2026, time.May, 28, 14, 0, 0, 0, time.UTC) := deadlinetime.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC).Add(time.Duration(offsetHours2) * time.Hour)12  isBefore→ false := checktime.Date(2026, time.May, 28, 14, 0, 0, 0, time.UTC).Before(deadlinetime.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC))13  isAfter→ true := checktime.Date(2026, time.May, 28, 14, 0, 0, 0, time.UTC).After(deadlinetime.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC))1415  fmt.Println("offsetHours=", offsetHours2)16  fmt.Println("check=", checktime.Date(2026, time.May, 28, 14, 0, 0, 0, time.UTC).Format("15:04"))17  fmt.Println("before=", isBeforefalse)18  fmt.Println("after=", isAftertrue)19}
    outputoffsetHours= 2
check= 14:00
before= false
after= true

  1. offsetHours ← -1, deadline ← time.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC)

    8func main() {9  var offsetHours→ -1 = -110  deadline→ time.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC) := time.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC)11  check→ time.Date(2026, time.May, 28, 11, 0, 0, 0, time.UTC) := deadlinetime.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC).Add(time.Duration(offsetHours-1) * time.Hour)12  isBefore→ true := checktime.Date(2026, time.May, 28, 11, 0, 0, 0, time.UTC).Before(deadlinetime.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC))13  isAfter→ false := checktime.Date(2026, time.May, 28, 11, 0, 0, 0, time.UTC).After(deadlinetime.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC))1415  fmt.Println("offsetHours=", offsetHours-1)16  fmt.Println("check=", checktime.Date(2026, time.May, 28, 11, 0, 0, 0, time.UTC).Format("15:04"))17  fmt.Println("before=", isBeforetrue)18  fmt.Println("after=", isAfterfalse)19}
    outputoffsetHours= -1
check= 11:00
before= true
after= false

  1. offsetHours ← 5, deadline ← time.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC)

    8func main() {9  var offsetHours→ 5 = 510  deadline→ time.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC) := time.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC)11  check→ time.Date(2026, time.May, 28, 17, 0, 0, 0, time.UTC) := deadlinetime.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC).Add(time.Duration(offsetHours5) * time.Hour)12  isBefore→ false := checktime.Date(2026, time.May, 28, 17, 0, 0, 0, time.UTC).Before(deadlinetime.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC))13  isAfter→ true := checktime.Date(2026, time.May, 28, 17, 0, 0, 0, time.UTC).After(deadlinetime.Date(2026, time.May, 28, 12, 0, 0, 0, time.UTC))1415  fmt.Println("offsetHours=", offsetHours5)16  fmt.Println("check=", checktime.Date(2026, time.May, 28, 17, 0, 0, 0, time.UTC).Format("15:04"))17  fmt.Println("before=", isBeforefalse)18  fmt.Println("after=", isAftertrue)19}
    outputoffsetHours= 5
check= 17:00
before= false
after= true