第八行的表达式可更改，第三行的kexi决定的精度，小数值计算可将第五行的extended更为real或double

PROGRAM EQUANTION (input,output);

CONST

  kexi=0.0000001;

VAR

  a,b,c:extended;

FUNCTION fx(x:extended):extended;

  BEGIN

    fx:=ln(x)/ln(2);

  END;

BEGIN

  writeln(‘Please input a and b’，‘    Produced BY Chaos‘)

  read(a,b);

  c:=(a+b)/2;

  IF fx(c)=0

  THEN writeln(‘x=‘,c)

  ELSE Repeat

       IF fx(a)*fx(c)<0

       THEN b:=c

       ELSE a:=c;

       UNTIL abs(a-b)<kexi;

  IF fx(c)<>0

  THEN writeln(‘x=‘,a);

END.