(* Algorithmus 8.4 *)
FUNCTION adapt(a,b,fa,fm,fb,is: real): real ;
VAR h,m,i1,i2,fml,fmr,int: real;
    i:integer;
    stack : ARRAY[1..30] OF
             RECORD
                a,b,fa,fm,fb: real END;
    fertig : boolean;

     (* globale Funktion f : real *)
BEGIN
  (* Initialisierung und erster Eintrag *)
  i:=1; int:=0;
  stack[1].a:=a; stack[1].b:=b;stack[1].fa:=fa;
  stack[1].fm:=fm; stack[1].fb:=fb;
  REPEAT
    (* Eintrag holen *)
    a:=stack[i].a; b:=stack[i].b; fa:=stack[i].fa;
    fm:=stack[i].fm; fb:=stack[i].fb;
    i:=i-1;
    REPEAT
      m := (a+b)/2 ; h := (b-a)/4 ;
      fml:=f(a+h); fmr:=f(b-h);
      i1 := h/1.5*(fa+4*fm+fb) ;
      i2 := h/3*(fa+4*(fml+fmr)+2*fm+fb) ;
      i1 := (16*i2-i1)/15;
      fertig:=(is+(i1-i2) = is);
      IF fertig THEN
      BEGIN
        int:= int+i1;
        writeln(tf,a:10:5,b-a,i1);
      END
      ELSE
        BEGIN
          i:=i+1; IF i>30 THEN writeln('I>30');
          stack[i].a:=m; stack[i].b:=b; stack[i].fa:=fm;
          stack[i].fm:=fmr; stack[i].fb:=fb;
          b:=m; fb:=fm;fm:=fml;
        END;
    UNTIL fertig;
  UNTIL i=0;
  adapt:=int;
END;