langs a-z

Task/Mutual-recursion/Pascal/mutual-recursion.pascal

@@ -0,0 +1,34 @@
+Program MutualRecursion;
+
+{M definition comes after F which uses it}
+function M(n : Integer) : Integer; forward;
+
+function F(n : Integer) : Integer;
+begin
+   if n = 0 then
+      F := 1
+   else
+      F := n - M(F(n-1));
+end;
+
+function M(n : Integer) : Integer;
+begin
+   if n = 0 then
+      M := 0
+   else
+      M := n - F(M(n-1));
+end;
+
+var
+   i : Integer;
+
+begin
+   for i := 0 to 19 do begin
+      write(F(i) : 4)
+   end;
+   writeln;
+   for i := 0 to 19 do begin
+      write(M(i) : 4)
+   end;
+   writeln;
+end.