[Golang Float Tricks] golang float tricks #go

float_precision_round.go

package main

import (
	"fmt"
	"math"
)

func main() {
	var a, b, c, d float64

	a = 10.000000000000001
	b = 9.99999999999999
	c = 61.599999999999994
	d = 61.600000000000006
	fmt.Println(ToFixed(a, 2))
	fmt.Println(ToFixed(b, 2))
	fmt.Println(ToFixed(c, 2))
	fmt.Println(ToFixed(d, 2))
}

//use in rateConversion
func ToFixed(num float64, precision uint) float64 {
	output := math.Pow(10, float64(precision))
	return float64(round(num*output)) / output
}

func round(num float64) int {
	return int(num + math.Copysign(0.5, num))
}