a)

Program FNG;
Uses crt;
Var s: extended;
    i: byte;
Begin
        Clrscr;
        s:=0; i:=1;
        While i<=100 do
        Begin
                s:=s+1/i;
                inc(i);
        End;

        Write(s:0:2);
        Readln
End.

b)

Program FNG;
Uses crt;
Var s: extended;
    i: longint;
Begin
        Clrscr;
        s:=0;
        For i:=1 to 100 do
                s:=s+1/i;

        Write(s:0:2);
        Readln
End.

Câu lệnh for ... do :

uses crt;

var i : integer; s : real;

begin

s :=0;

for i:=1 to 100 do S:= s+1/i;

writeln('Tong S la :', s);

readln 

end.

Câu lệnh while... do :

uses crt;

var i :integer; s : real;

begin

s:= 0;

while i <= 100 do

Begin

s := s+1/i;

i :=i+1;

end;

writeln('Tong S =', s);

readln

end.