throw exception for invalid input

src/game/Frame.java

@@ -9,8 +9,13 @@ public class Frame {
 		this.score = previousScore;
 	}
 	
-	public void enterPoint(int point) {
+	public void enterPoint(int point) throws Exception {
+		if(point < 0 || point > 10)
+			throw new Exception("invalid point: [0, 10]");
+		
 		if (firstLance == -1) this.firstLance = point;
+		else if (point + this.firstLance > 10)
+			throw new Exception("invalid point: [0, " + (10 - this.firstLance) + "]");
 		else this.secondLance = point;
 		this.score += point;
 	}