PROGRAM d5r6(input,output);
(* driver for routine CHINT *)
LABEL 10,99;
CONST
   nval=40;
   pio2=1.5707963;
TYPE
   glcarray=ARRAY [1..nval] OF real;
VAR
   a,b,x : real;
   i,mval : integer;
   c,cint : glcarray;

FUNCTION func(x: real): real;
BEGIN
   func := sqr(x)*(sqr(x)-2.0)*sin(x)
END;

FUNCTION fint(x: real): real;
BEGIN
   fint := 4.0*x*(sqr(x)-7.0)*sin(x)
      -(sqr(sqr(x))-14.0*sqr(x)+28.0)*cos(x)
END;

(*$I MODFILE.PAS *)
(*$I CHEBFT.PAS *)

(*$I CHEBEV.PAS *)

(*$I CHINT.PAS *)

BEGIN
   a := -pio2;
   b := pio2;
   chebft(a,b,c,nval);
(* test integral *)
10:   writeln;
   writeln('How many terms in Chebyshev evaluation?');
   write('Enter n between 6 and ',nval:2,
         '. (n := 0 to end).  ');
   readln(mval);
   IF ((mval <= 0) OR (mval > nval)) THEN GOTO 99;
   chint(a,b,c,cint,mval);
   writeln;
   writeln('x':9,'actual':14,'Cheby. integ.':16);
   FOR i := -8 to 8 DO BEGIN
      x := i*pio2/10.0;
      writeln(x:12:6,fint(x)-fint(-pio2):12:6,
            chebev(a,b,cint,mval,x):12:6)
   END;
   GOTO 10;
99:
END.