PROGRAM EPIZYKLOIDE (INPUT,OUTPUT,GRAPHIC);                 
(* 1.10.1986 FLORIAN MATTHES                              *)
(* S. AUFGABE 9 IN KAPITEL 2.8                            *)
   CONST R        = 45;                                     
         R1       = 55;                                     
         A        = 65;                                     
         DELTAPHI = 0.15;                                   
   VAR   PHI      : REAL;                                   
         RPLUSR1  : REAL;                                   
         Q        : REAL;                                   
         X,Y      : INTEGER;                                
                                                            
BEGIN                                                       
  PHI:=0.0; RPLUSR1:= R + R1;                               
  Q:= RPLUSR1 / R;                                          
  GRAPHIC(1,1); COLOR(2,1); COLOR(1,2);                     
                                                            
  REPEAT                                                    
    X:= ROUND(RPLUSR1 * COS(PHI) -  A * COS (Q * PHI))      
        + 160;                                              
    Y:= ROUND(RPLUSR1 * SIN(PHI) -  A * SIN (Q * PHI))      
        + 100;                                              
    IF PHI=0.0 THEN                                         
      LOCATE(X,Y)                                           
    ELSE                                                    
      DRAW (1,,X,Y);                                        
    PHI:= PHI + DELTAPHI;                                   
  UNTIL KEYPRESSED;                                         
  GRAPHIC(0);                                               
END.