adding a few asserts for ex19

object.c

@@ -46,6 +46,7 @@ int Object_attack(void *self, int damage)
 
 void *Object_new(size_t size, Object proto, char *description)
 {
+    assert(description != NULL);
     // setup the default functions in case they aren't set
     if(!proto.init) proto.init = Object_init;
     if(!proto.describe) proto.describe = Object_describe;
@@ -56,6 +57,7 @@ void *Object_new(size_t size, Object proto, char *description)
     // this seems weird, but we can make a struct of one size,
     // then point a different pointer at it to "cast" it
     Object *el = calloc(size, 1);
+    assert(el != NULL);
     *el = proto;
 
     // copy the description over