1 files changed, 4 insertions, 1 deletions

diff --git a/balls.h b/balls.h
index 8e66ae0..69adde9 100644
--- a/balls.h
+++ b/balls.h
@@ -1,5 +1,6 @@
 #include <u.h>
 #include <libc.h>
+#include <stdio.h>
 #include <draw.h>
 #include <cursor.h>
 
@@ -31,4 +32,6 @@ Point ptaddv(Point p, Vec v);
 Vec V(double x, double y);
 Vec Vpt(Point p, Point q);
 
-int iscollision(Point p, Point q);
\ No newline at end of file
+int iscollision(Point p, Point q);
+void collideball(Ball *b1, const Ball *b2);
+void collidewall(Ball *b, Rectangle wall);