fix compilation errors

main/main.go

@@ -9,7 +9,7 @@ import (
 )
 
 func main() {
-	num := 1000
+	num := int64(1000)
 	if len(os.Args) > 1 {
 		n, err := strconv.ParseInt(os.Args[1], 0, 64)
 		if err != nil {
@@ -22,7 +22,7 @@ func main() {
 	}
 
 	price, bidder := auctionsim.RunAuction(
-		auctionsim.CappedBidderGenerator{
+		&auctionsim.CappedBidderGenerator{
 			G:   auctionsim.NormalestBidderGenerator(),
 			Lim: num,
 		},