a)
Program FNG;
Uses crt;
Var n,i,s: longint;
Begin
Clrscr;
Write('Nhap n: '); Readln(n);
For i:=1 to n do
s:=s+i;
Write('S = ',s);
Readln
End.
b)
Program FNG;
Uses crt;
Var n,i,s: longint;
Begin
Clrscr;
Write('Nhap n: '); Readln(n);
For i:=1 to n do
If i mod 2 = 0 then
s:=s+i;
Write('S = ',s);
Readln
End.
c)
Program FNG;
Uses crt;
Var n,i,s: longint;
Begin
Clrscr;
Write('Nhap n: '); Readln(n);
For i:=1 to n do
If i mod 2 = 1 then
s:=s+i;
Write('S = ',s);
Readln
End.