Cleaning up rolls implementation

to be a bit more idiomatic, I suppose.

algs4/src/go/algs4-rolls/main.go

@@ -11,25 +11,27 @@ import (
 )
 
 const (
-	USAGE string = "Usage: algs4-rolls <nrolls>"
-	SIDES        = 6
+	USAGE = "Usage: algs4-rolls <nrolls>"
+	SIDES = 6
 )
 
+func die(err error) {
+	fmt.Println("Wat.", err)
+	os.Exit(2)
+}
+
 func main() {
 	if len(os.Args) < 2 {
 		fmt.Println(USAGE)
 		os.Exit(1)
 	}
 
-	nrolls, err := strconv.ParseInt(os.Args[1], 10, 32)
+	nrolls, err := strconv.Atoi(os.Args[1])
 	if err != nil {
-		fmt.Println("Wat.", err)
-		os.Exit(2)
+		die(err)
 	}
 
-	rolls, err := algs4.Rolls(nrolls)
-
-	for i := 1; i <= algs4.ROLL_SIDES; i += 1 {
-		fmt.Println(rolls[i])
+	for _, roll := range algs4.Rolls(nrolls) {
+		fmt.Println(roll)
 	}
 }