allows user to specify max for rand

main.go

@@ -2,7 +2,9 @@ package main
 
 import (
 	"container/heap"
+	"flag"
 	"fmt"
+	"math"
 	"math/rand"
 	"os"
 	"sort"
@@ -12,8 +14,12 @@ import (
 
 const usage = "smerge [count, count, ... count]"
 
+var max = flag.Int("max", 1000, "maximum random number for each source")
+
 func main() {
-	args := os.Args[1:]
+	flag.Parse()
+
+	args := flag.Args()
 	if len(args) < 1 {
 		fmt.Fprintf(os.Stderr, "usage: %v\n", usage)
 		os.Exit(1)
@@ -26,20 +32,21 @@ func main() {
 			os.Exit(1)
 		}
 
-		srcs = append(srcs, source(i))
+		srcs = append(srcs, source(i, *max))
 	}
+	f := fmt.Sprintf("%%%dd\n", int(math.Log10(float64(*max))))
 	for i := range merge(srcs...) {
-		fmt.Printf("%20d\n", i)
+		fmt.Printf(f, i)
 	}
 }
 
-func source(c int) <-chan int {
+func source(c, max int) <-chan int {
 	out := make(chan int)
 	go func() {
 		vals := make([]int, c)
 		src := rand.New(rand.NewSource(time.Now().UnixNano()))
 		for i := 0; i < c; i++ {
-			vals[i] = src.Int()
+			vals[i] = src.Intn(max)
 		}
 
 		sort.Ints(vals)