Playing with counters and flips

algs4/src/meatballhat.com/algs4-flips/main.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"crypto/rand"
+	"fmt"
+	"math"
+	"math/big"
+	"os"
+	"strconv"
+)
+
+import (
+	"meatballhat.com/algs4"
+)
+
+const USAGE string = "Usage: algs4-flips <nflips>"
+
+func main() {
+	if len(os.Args) < 2 {
+		fmt.Println(USAGE)
+		os.Exit(1)
+	}
+
+	nflips, err := strconv.ParseInt(os.Args[1], 10, 32)
+	if err != nil {
+		fmt.Println("Wat.", err)
+		os.Exit(2)
+	}
+
+	heads := algs4.NewCounter("heads")
+	tails := algs4.NewCounter("tails")
+
+	randMax := big.NewInt(2)
+
+	for t := int64(0); t < nflips; t += int64(1) {
+		n, err := rand.Int(rand.Reader, randMax)
+		if err != nil {
+			fmt.Println("Ugh:", err)
+			os.Exit(4)
+		}
+
+		if n.Int64() < 1 {
+			heads.Increment()
+		} else {
+			tails.Increment()
+		}
+	}
+
+	fmt.Println(heads)
+	fmt.Println(tails)
+
+	d := heads.Tally() - tails.Tally()
+
+	fmt.Printf("delta: %d\n", int(math.Abs(float64(d))))
+}

algs4/src/meatballhat.com/algs4/counter.go

@@ -0,0 +1,37 @@
+package algs4
+
+import (
+	"fmt"
+)
+
+type Counter struct {
+	name  string
+	count int
+}
+
+func NewCounter(name string) *Counter {
+	counter := &Counter{}
+	counter.name = name
+	return counter
+}
+
+func (c *Counter) Increment() {
+	c.count += 1
+}
+
+func (c *Counter) Tally() int {
+	return c.count
+}
+
+func (c *Counter) String() string {
+	return fmt.Sprintf("%d %s", c.count, c.name)
+}
+
+func (c *Counter) Cmp(other *Counter) int {
+	if c.count < other.count {
+		return -1
+	} else if c.count > other.count {
+		return 1
+	}
+	return 0
+}