1 files changed, 10 insertions, 2 deletions

diff --git a/balls.h b/balls.h
index 3205959..b69eea4 100644
--- a/balls.h
+++ b/balls.h
@@ -1,3 +1,5 @@
+#include <stdlib.h>
+
 typedef struct {
 	double x, y;
 } Point;
@@ -13,11 +15,17 @@ typedef struct {
 typedef struct {
 	Point p; /* position [m] */
 	Vector v; /* velocity [m/s] */
-	double m; /* mass [kg] */
 	double r; /* radius [m] */
+	double m; /* mass [kg] */
 } Ball;
 
 Point ptAddVec(Point p, Vector v);
+Point Pt(double x, double y);
 Rectangle insetRect(Rectangle r, double n);
+Point randPtInRect(Rectangle r);
+
+int isCollision(Point p1, double r1, Point p2, double r2);
+void collideWall(Ball *b, Rectangle wall);
 
-void collideWall(Ball *b, Rectangle wall);
\ No newline at end of file
+int randInt(int lo, int hi);
+double randDouble(double lo, double hi);