Comment 1 by islandberry23:

See http://golang.org/ref/spec#Constant_expressions.  The expression 3*3 + 4*4 is
untyped, not an int.

Comment 2 by blair@orcaware.com:

Thanks, however, constants are first introduced on slide #16.  Being a Go newbie, I find
the text confusing and it implies that the float64() is required when it isn't, unlike
the `int(f)` which is required.

Comment 3 by sieben07:

package main
import (
    "fmt"
    "math"
)
func main() {
    var x, y int = 3, 4
    var f float64 = math.Sqrt(float64(x*x + y*y))
    var z int = int(f)
    fmt.Println(x, y, z)
}
since we have x and y int = 3, 4
it would make sense:
var f float64 = math.Sqrt(float64(x*x + y*y))
Now the program and the text would fit.

Comment 4:

Labels changed: added repo-tour, release-go1.2.1.

Comment 5:

Labels changed: removed release-go1.2.1.

Comment 6:

Owner changed to @adg.