How to divide numbers in Go correctly

The result of performing integer division in Go can be surprising if you’re new to the language. For example, 20 ÷ 8 gives 2 instead of 2.5.

func main() {
	fmt.Println(20 / 8) // 2
}

Both numbers are treated as untyped integer constants and operations on untyped constants of the same type yields a result of the same kind. This is why we get 2 as the result of the operation above.

For operations between untyped constants of different types, the result would be in the kind that appears later in this list: integer, rune, floating-point, complex. For example, an operation between an untyped floating-point constant and an untyped integer constant will yield a floating-point constant.

func main() {
	fmt.Println(20.0 / 8) // 2.5
	fmt.Println(20 / 8.0) // 2.5
}

When dividing variables, ensure both are converted to the float64 type first.

func main() {
	a := 20
	b := 3
	fmt.Println(float64(a) / float64(b)) // 6.666666666666667
	// Don't do this
	fmt.Println(float64(a / b)) // 6
}

Thanks for reading, and happy coding!

• #golang