how can I force division to be floating point in Go?

I have the following code snippet:

package main

import("fmt";"flag")

func main() {
    var a = flag.Int("a",0,"divident")
    var b = flag.Int("b",1,"divisor")
    flag.Parse()

    fmt.Printf("%f",*a / *b )
}

For -a 3 and -b 2 command line arguments, the output is: %!f(int=1)

What is the best / most elegant way to force this division to be floating point?