Bài 1:

#include <bits/stdc++.h>

using namespace std;

long long x,n,i,t;

int main()

{

cin>>n;

t=0;

for (i=1; i<=n; i++)

{

cin>>x;

if ((x<0) and (x%2!=0)) t=t+x;

}

cout<<t;

return 0;

}

1. Uses crt;

var n,i: integer;

begin clrscr;

readln(n);

for i:=1 to n do write(i:3);

readln;

end.

2. Uses crt;

var n,i: integer;

begin clrscr;

readln(n);

for i:=1 to n do if(i mod 2 = 0) then write(i:3);

readln;

end.

1. Uses crt;

var n,i: integer;

begin clrscr;

readln(n);

for i:=1 to n do write(i:3);

readln;

end.

2. Uses crt;

var n,i: integer;

begin clrscr;

readln(n);

for i:=1 to n do if(i mod 2 = 0) then write(i:3);

readln;

end.

1.

program InDaySoTuNhien;
var n, i: integer;
begin
   write('Nhap so nguyen duong n: ');
   readln(n);

   writeln('Day so tu 1 den ', n, ' la:');
   for i := 1 to n do
      write(i, ' ');
end.

2.

program InSoChan;
var
   n, i: integer;
begin
   write('Nhap so nguyen n: ');
   readln(n);

   writeln('Cac so nguyen chan trong khoang tu 1 den ', n, ' la:');
   for i := 1 to n do
   begin
      if i mod 2 = 0 then
         write(i, ' ');
   end;
end.

uses crt;

var n,m,i,dem,t,t1,d1:integer;

//chuongtrinhcon

function ktnt(var n:integer):boolean;

var i:integer;

kt:boolean;

begin

kt:=true;

for i:=2 to trunc(sqrt(n)) do 

  if n mod i=0 then kt:=false;

if (kt=true) then ktnt:=true

else ktnt:=false;

end;

//chuongtrinhchinh

begin

clrscr;

readln(n,m);

if (ktnt(n)=true) then writeln(n,' la so nguyen to')

else writeln(n,' ko la so nguyen to');

dem:=0;

t:=0;

for i:=2 to n do 

  if (ktnt(i)=true) then

begin

write(i:4);

t:=t+i;

dem:=dem+1;

end;

writeln;

writeln(t,' ',dem);

t1:=0;

d1:=0;

for i:=n to m do 

  if ktnt(i)=true then

begin

write(i:4);

t1:=t1+i;

inc(d1);

end;

writeln;

writeln(t1,' ',d1);

readln;

end.

Program HOC24;

var i,n: integer;

s: longint;

begin

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

s:=0;

for i:=1 to n do if i mod 2=0 then s:=s+i;

write('S = ',s);

readln

end.

pascal

program sum_of_evens;

var
  i, n, sum: integer;

begin
  write('Enter a positive integer: ');
  readln(n);
  
  sum := 0;
  
  for i := 2 to n step 2 do
  begin
    sum := sum + i;
  end;
  
  writeln('The sum of even numbers from 2 to ', n, ' is ', sum);
end.

Bài 1: 

uses crt;

var n,i,kt:integer;

begin

clrscr;

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

kt:=0;

for i:=2 to n-1 do 

 if n mod i=0 then kt:=1;

if (kt=0) and (n>1) then writeln(n,' la so nguyen to')

else writeln(n,' khong la so nguyen to');

readln;

end.

Bài 2: 

uses crt;

var n,i:integer;

begin

clrscr;

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

for i:=1 to n do 

 if n mod i=0 then write(i:4);

readln;

end.

c1: 

#include <bits/stdc++.h>

using namespace std;

long long i,n,s;

int main()

{

cin>>n;

s=1;

for (i=1; i<=n; i++) s=s*i;

cout<<s;

return 0;

}

Câu 2: 

#include <bits/stdc++.h>

using namespace std;

long long i,n,s;

int main()

{

cin>>n;

s=1;

for (i=1; i<=n; i++) if (i%2==0) s=s*i;

cout<<s;

return 0;

}