# Golang : Display float in 2 decimal points and rounding up or down

Tags : golang math-pow float round-up round-down decimal-points

We will cover 2 items for this tutorial.

First, we will learn how to display a float number in decimal points with the `fmt.Printf()`

function. The `%0.2f`

inside `fmt.Printf()`

function tells Golang to display up to 2 decimal points. To increase the precision, simply adjust the number from `%0.2f`

to `%0.#f`

. # being the number of digits to display the after the decimal point.

Next, Golang math package lacks of functions to do rounding on float numbers. The code example below has 3 functions - one to do rounding, next for rounding up and another to do rounding down for a float value.

Here you go!

```
package main
import (
"fmt"
"math"
)
func Round(input float64) float64 {
if input < 0 {
return math.Ceil(input - 0.5)
}
return math.Floor(input + 0.5)
}
func RoundUp(input float64, places int) (newVal float64) {
var round float64
pow := math.Pow(10, float64(places))
digit := pow * input
round = math.Ceil(digit)
newVal = round / pow
return
}
func RoundDown(input float64, places int) (newVal float64) {
var round float64
pow := math.Pow(10, float64(places))
digit := pow * input
round = math.Floor(digit)
newVal = round / pow
return
}
func main() {
var f float64 = 123.123456
fmt.Printf("%0.2f \n", f)
fmt.Printf("%0.2f \n", Round(f)) // round half
fmt.Printf("%0.2f \n", RoundUp(f, 2))
fmt.Printf("%0.2f \n", RoundDown(f, 2))
}
```

**NOTE : Change value of f to -123.123456 and see how it goes.**

Output :

123.12

123.00

123.13

123.12

References :

http://golang.org/pkg/math/#Ceil

Tags : golang math-pow float round-up round-down decimal-points

##### By Adam Ng

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