--- dwm.c	2021-10-02 14:22:28.034782413 +0100
+++ dwm.c	2021-10-02 14:27:54.599845767 +0100
@@ -183,8 +183,10 @@ static void maprequest(XEvent *e);
 static void monocle(Monitor *m);
 static void motionnotify(XEvent *e);
 static void movemouse(const Arg *arg);
+static unsigned int nexttag(void);
 static Client *nexttiled(Client *c);
 static void pop(Client *);
+static unsigned int prevtag(void);
 static void propertynotify(XEvent *e);
 static void quit(const Arg *arg);
 static Monitor *recttomon(int x, int y, int w, int h);
@@ -208,6 +210,8 @@ static void sigchld(int unused);
 static void spawn(const Arg *arg);
 static void tag(const Arg *arg);
 static void tagmon(const Arg *arg);
+static void tagtonext(const Arg *arg);
+static void tagtoprev(const Arg *arg);
 static void tile(Monitor *);
 static void togglebar(const Arg *arg);
 static void togglefloating(const Arg *arg);