uses crt;

var n,i,t:integer;

begin

clrscr;

readln(n);

t:=0;

for i:=1 to n do

if i mod 2=0 then t:=t+i;

write(t);

readln;

end.

câu 1:

uses crt;

var p,i:integer;

begin

clrscr;

p:=1;i:=1;while i<=5 do

begin

p:=p*i;i:=i+1;

end;

write(p);

readln;

end. 

bai 2:

uses crt;var p,i:integer;begin    clrscr;    p:=1; i:=0;    while i <=10 do    begin

i:=i+1;        if (i mod 2<>0) then p:=p*i;    end;    write(p);    readln;end. bai 3:

uses crt;var n,i,p:integer;begin     clrscr;     write('nhap n: ');     readln(n);     i:=1;     p:=1;     while i<=n do     begin       if i mod 2=0 then p:=p*i;       i:=i+1;     end;     write(p);     readln;end.     

*Cách khác: Dùng for

Câu 1: 

uses crt;

var p,i:longint;

begin

p:=1;

for i:=1 to 4 do 

  p:=p*i;

writeln(p);

readln;

end.

Câu 2: 

uses crt;

var i,s:longint;

begin

clrscr;

s:=1;

for i:=1 to 10 do

  if i mod 2=1 then s:=s*i;

writeln(s);

readln;

end.

Câu 3: 

uses crt;

var n,i,s:longint;

begin

clrscr;

write('Nhap n='); readln(n);

s:=0;

for i:=1 to n do 

  if i mod 2=0 then s:=s+i;

writeln(s);

readln;

end.

uses crt;

var n,i:integer;

begin

clrscr;

readln(n);

for i:=1 to n do

if i mod 2=0 then write(i:4);

readln;

end.

for ... do

program Tinh_S;

uses crt;

var i,n:byte;

     S:longint;

begin

        writeln('Nhap so n='); readln(n);

       S:=0;

       for i:=1 to n do 

           if i mod 2=1 then S:=S+i;

       writeln('Tong cac so le nho hon hoac bang n la, S=',S)

       readln

end.

* While....do

Uses crt;

var n,i,k: integer;

begin clrscr;

readln(n);

i:=0;

while(i<=n) do begin

i:=i+1;

if(i mod 2<>0) then k:=k+i;

end;

writeln(k);

readln;

end.

* for...do

Uses crt;

var n,i,u: integer;

begin clrscr;

readln(n);

for i:=1 to n do if(i mod 2<>0) then u:=u+i;

writeln(u);

readln;

end.

#include <bits/stdc++.h>

using namespace std;

long long i,n;

int main()

{

cin>>n;

for (i=1; i<=n; i++) if (i%2==0) cout<<i<<" ";

return 0;

}

Var n,i,so:integer;

Begin

Write('Nhap n = ');readln(n);

Writeln('Cac so chan tu 1 den n la: ');

For i:=1 to n do

If i mod 2 = 0 then write(i,'   ');

Readln;

End.

Var n,i,so:integer;

Begin

Write('Nhap n = ');readln(n);

For i:=1 to n do

Begin

Write('Nhap so thu ',i,' = ');readln(so);

If so mod 2 = 0 then writeln(so);

End;

Readln;

End.