code 31095;
procedure COMFOUSER(N,THETA,A,RR,RI);
value N,THETA;integer N;real THETA,RR,RI;array A;
begin integer K;real C,CC,LAMBDA,H,DUN,UN,UN1;
   C:=COS(THETA);
   if C<-.5then 
   begin LAMBDA:= 4*COS(THETA/2)**2;UN:=DUN:=0;
          for K:=N"STEP"-1until 0do 
          begin UN:=DUN-UN;
                 DUN:=LAMBDA*UN-DUN+A[K]
          end;RR    :=DUN-LAMBDA/2*UN
   end else if C> .5then 
   begin LAMBDA:=-4*SIN(THETA/2)**2;UN:=DUN:=0;
          for K:=N"STEP"-1until 0do 
          begin UN:=DUN+UN;
                 DUN:=LAMBDA*UN+DUN+A[K]
          end;RR    :=DUN-LAMBDA/2*UN
   end else 
   begin CC:=C+C;UN:=UN1:=0;
          for K:=N"STEP"-1until 1do 
          begin H:=CC*UN-UN1+A[K];
                 UN1:=UN;UN:=H
          end;RR    :=A[0]+UN*C-UN1
   end;RI:=UN*SIN(THETA)
end COMFOUSER;
        eop