diff --git a/src/c/funktionen.h b/src/c/funktionen.h
index d2387c9..0a83972 100644
--- a/src/c/funktionen.h
+++ b/src/c/funktionen.h
@@ -34,4 +34,7 @@ float floorValue(float x);
 // Function to calculate the ceiling value of a number
 float ceilingValue(float x);
 
+// Function to calculate the absolute difference between two numbers
+float absoluteDifference(float x, float y);
+
 #endif
\ No newline at end of file