Golang simple 1 point decimal counter

[Nikola-Milovic]

I am trying to achieve a counter that will count how many seconds have passed in my game. It’s only seconds based and I need it for a game server project. All I want to do, literally all I want to do is 0 + 0.2 and then next tick 0.2+0.2, 0.4+0.2 … This cannot be achieved with floats as eventually it will be 1.99999999998 instead of 2 and that would ruin the calculations. I’ve looked into Big Int, fixed precision libraries but I am not sure what should I use. I don’t want too much overhead as this is called 5-10 times a second. A simple 0 + 0.2 would work perfectly and that way I can get whether or not a second or half a second has passed and I can store the previous time in a simple number.

Idea is that player would have a timestamp of when the last action was performed, I’d check against the time if X time has passed ( time- lastTime > X) and then if that’s true I’d perform something. I have access to the servers tick rate which I set to 0.2. I can always go with OS time if nothing else. Any recommendations on what to do?

[ermanimer]

you can use 200 milliseconds with an integer data type (int64).

[Nikola-Milovic]

Care to elaborate? I’d much prefer having smaller decimals, but I guess having bigger numbers could do the same thing

[j-forster (Johann Forster)]

If you use 200ms as a fixed step size, you can create a custom integer that uses exactly 200ms as one step.

package main

import (
	"fmt"
)

type Counter int64 // 200ms step
const (
	Step200MS  Counter = 1
	StepSecond         = 5 * Step200MS
)

func (c Counter) String() string {
	return fmt.Sprintf("%d.%ds", c/5, c%5*200)
}

func main() {
	var c Counter

	c += Step200MS
	fmt.Printf("time: %s\n", c)

	c++ // equals 200ms
	fmt.Printf("time: %s\n", c)

	c += StepSecond
	fmt.Printf("time: %s\n", c)
}

See https://play.golang.org/p/7f7RyfvLK66

[ermanimer]

sure i could but @j-forster gave a great example