Data commit

Task/Averages-Mean-angle/Pascal/averages-mean-angle.pas

@@ -0,0 +1,71 @@
+program MeanAngle;
+{$IFDEF DELPHI}
+  {$APPTYPE CONSOLE}
+{$ENDIF}
+uses
+  math;// sincos and atan2
+type
+  tAngles = array of double;
+
+function MeanAngle(const a:tAngles;cnt:longInt):double;
+// calculates mean angle.
+// returns 0.0 if direction is not sure.
+const
+  eps = 1e-10;
+
+var
+  i : LongInt;
+  s,c,
+  Sumsin,SumCos : extended;
+begin
+  IF cnt = 0 then
+  Begin
+    MeanAngle := 0.0;
+    EXIT;
+  end;
+
+  SumSin:= 0;
+  SumCos:= 0;
+  For i := Cnt-1 downto 0 do
+  Begin
+    sincos(DegToRad(a[i]),s,c);
+    Sumsin := sumSin+s;
+    SumCos := sumCos+c;
+  end;
+  s := SumSin/cnt;
+  c := sumCos/cnt;
+  IF c > eps then
+    MeanAngle := RadToDeg(arctan2(s,c))
+  else
+    // Not meaningful
+    MeanAngle := 0.0;
+end;
+
+Procedure OutMeanAngle(const a:tAngles;cnt:longInt);
+var
+  i : longInt;
+Begin
+  IF cnt > 0 then
+  Begin
+    write('The mean angle of [');
+    For i := 0 to Cnt-2 do
+      write(a[i]:0:2,',');
+    write(a[Cnt-1]:0:2,'] => ');
+    writeln(MeanAngle(a,cnt):0:16);
+  end;
+end;
+
+var
+  a:tAngles;
+Begin
+  setlength(a,4);
+
+  a[0] := 350;a[1] := 10;
+  OutMeanAngle(a,2);
+  a[0] := 90;a[1] := 180;a[2] := 270;a[3] := 360;
+  OutMeanAngle(a,4);
+  a[0] := 10;a[1] := 20;a[2] := 30;
+  OutMeanAngle(a,3);
+
+  setlength(a,0);
+end.