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>"
+	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)
 	}
 }

algs4/src/go/algs4/rolls.go

@@ -6,17 +6,20 @@ import (
 
 const ROLL_SIDES = 6
 
-func Rolls(nrolls int64) ([]*Counter, error) {
-	rolls := make([]*Counter, ROLL_SIDES+1)
-	for i := 1; i <= ROLL_SIDES; i += 1 {
-		rolls[i] = NewCounter(fmt.Sprintf("%d's", i))
+func Rolls(nrolls int) []*Counter {
+	var rolls []*Counter
+
+	for i := 0; i < ROLL_SIDES; i++ {
+		rolls = append(rolls, NewCounter(fmt.Sprintf("%d's", i+1)))
 	}
 
 	randMax := float64(ROLL_SIDES)
+	zero := float64(0.0)
 
-	for t := int64(0); t < nrolls; t++ {
-		rolls[int(RandomUniform(float64(0.0), randMax))+1].Increment()
+	for t := 0; t < nrolls; t++ {
+		result := int(RandomUniform(zero, randMax))
+		rolls[result].Increment()
 	}
 
-	return rolls, nil
+	return rolls
 }