MODULE graph1;  (* DEE 2023-07-21 *)
  (* From PASCAL: user manual and report, Second Edition, pg. 30.
   * graphic representation of a function
   * f(x) = exp(-x) * sin(2*pi*x
   *)
  FROM MathLib0 IMPORT exp, sin;
  FROM InOut IMPORT Write, WriteLn;

  CONST d = 0.0625; (*1/16, 16 lines for interval [x,x+1]*)
        s = 32; (*32 character widths for interval [y,y+1]*)
        h = 34; (*character position of x-axis*)
        c = 6.28318; (*2*pi*) lim = 32;
  VAR x, y: REAL; i, n: INTEGER;
BEGIN
  FOR i := 0 TO lim DO
    x := d*FLOAT(i); y := exp(-x)*sin(c*x);
    n := TRUNC((FLOAT(s)*y) + 0.5) + h; (* 0.5 to round before truncating. *)
    REPEAT Write(' '); DEC(n)
    UNTIL n = 0;
    Write('*'); WriteLn
  END
END graph1.