USES SPLIN;
{ Porovnava hodnoty funkce cos x s hodnotou ziskanou pomoci splinu
  zadavaji se derivace na okraji jako okraj. podm.
  vysledek se pise do souboru SPLB.DAT
  nbod = pocet zadanych hodnot, ndel - pocet vypisovanych vysledky splinu}
const
  pi = 3.141592;
var
   X,Y, Y2 : RealArrayNP;
   xmax,xmin,yp1,ypn,dx,y21,xh,ygs,yfs,dx1: Real;
   i,nbod,ndel : integer;
   f1 : text;
BEGIN
   ASSIGN(f1,'splb.dat');
   REWRITE(f1);
   Writeln('ZADEJ xmin,xmax,nbod (pocet bodu v tabulce)');
   Readln(xmin,xmax,nbod);
   dx := (xmax-xmin)/(nbod - 1);
   FOR i := 1 to nbod DO BEGIN
      x[i] := xmin + (i-1)*dx;
      y[i] := cos(x[i])
   END;
   Writeln (' Zadej derivaci y pro xmin; xmax; ndel(pocet vyslednych bodu');
   Readln(yp1,ypn,ndel);
   Spline(X,Y,nbod,yp1,ypn,Y2);
   dx1 := (xmax-xmin)/(ndel - 1);
   writeln('    x         yteor         ysplin     x[i]   y[i] ');
   FOR i := 1 to ndel DO BEGIN
       xh := xmin+(i-1)*dx1;
       yfs := cos(xh);
       splint(x,y,y2,nbod,xh,ygs);
       IF(i <= nbod) THEN BEGIN
            writeln(xh,yfs,ygs,x[i],y[i]);
            writeln(f1,xh:10:6,' ',yfs:13:-4,' ',ygs:13:-4,' ',
                    x[i]:13:-4,' ',y[i]:13:-4)
            END
       ELSE BEGIN
            writeln(xh,yfs,ygs);
            writeln(f1,xh:10:6,' ',yfs:13:-4,' ',ygs:13:-4);
       END;
       END;
   CLOSE(f1)
END.