Câu 2: 

uses crt;

var a,b:integer;

{-----------------chuong-trinh-con-------------------}

function ucln(x,y:integer):integer;

var i,uc:integer;

begin

if x<y then 

begin

uc:=1;

for i:=1 to x do 

  if (x mod i=0) and (y mod i=0) then  

begin

if uc<i then uc:=i;

end;

end

else begin

uc:=1;

for i:=1 to y do 

  if (x mod i=0) and (y mod i=0) then  

begin

if uc<i then uc:=i;

end;

end;

ucln:=uc;

end;

{--------------------------chuong-trinh-chinh------------------------}

begin

clrscr;

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

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

writeln(a,'/',b,'=',a div ucln(a,b),'/',b div ucln(a,b));

readln;

end.

Câu 1: 

const fi='songuyen.inp'

fo='tong.out'

var f1,f2:text;

a:array[1..100]of integer;

i,n,t:integer;

begin

assign(f1,fi); reset(f1);

assign(f2,fo); rewrite(f2);

n:=0;

while not eoln(f1) do 

  begin

n:=n+1;

read(f1,a[n]);

end;

t:=0;

for i:=1 to n do 

  if a[i] mod 2=0 then t:=t+a[i];

writeln(f2,t);

close(f1);

close(f2);

end.

Câu 1:

const fi1='nguyen1.inp';
fi2='nguyen2.inp';
fo='songuyen.inp';
var f1,f2,f3:text;
a:array[1..10000]of integer;
i,dem:integer;
begin
assign(f1,fi1); reset(f1);
assign(f2,fi2); reset(f2);
assign(f3,fo); rewrite(f3);
dem:=0;
while not eof(f1) do
begin
inc(dem);
read(f1,a[dem]);
end;
while not eof(f2) do
begin
inc(dem);
read(f2,a[dem]);
end;
for i:=1 to dem do
write(f3,a[i]:4);
close(f1);
close(f2);
close(f3);
end.

Câu 2:

uses crt;
const fi='vanban.txt';
var f1:text;
st:array[1..255]of string;
dem:integer;
begin
clrscr;
assign(f1,fi); reset(f1);
dem:=0;
while not eof(f1) do
begin
inc(dem);
readln(f1,st[dem]);
end;
writeln('So dong cua tep ',fi,' la: ',dem);
close(f1);
readln;
end.

Câu 3:

const fi='nguon.txt';
fo='dich.txt';
var f1,f2:text;
st:array[1..255]of string;
i,dem:integer;
begin
assign(f1,fi); reset(f1);
assign(f2,fo); rewrite(f2);
dem:=0;
while not eof(f1) do
begin
inc(dem);
readln(f1,st[dem]);
end;
for i:=1 to dem do
writeln(f2,st[i]:4);
close(f1);
close(f2);
end.

Câu 4:

const fi='dulieu.int';
fo='sochan.out';
var f1,f2:text;
a:array[1..255]of integer;
i,dem:integer;
begin
assign(f1,fi); reset(f1);
assign(f2,fo); rewrite(f2);
dem:=0;
while not eoln(f1)do
begin
inc(dem);
read(f1,a[dem]);
end;
for i:=1 to dem do
if a[i] mod 2=0 then write(f2,a[i]:4);
close(f1);
close(f2);
end.

Câu 5:

const fi='dulieu.int';
fo='dulieu.out';
var f1,f2:text;
a:array[1..255]of integer;
i,n,tam,j:integer;
begin
assign(f1,fi); reset(f1);
assign(f2,fo); rewrite(f2);
readln(f1,n);
for i:=1 to n do
read(f1,a[i]);
for i:=1 to n-1 do
for j:=i+1 to n do
if a[i]<a[j] then
begin
tam:=a[i];
a[i]:=a[j];
a[j]:=tam;
end;
for i:=1 to n do
write(f2,a[i]:4);
close(f1);
close(f2);
end.

const fi='songuyen.inp'

fo='tong.out'

var f1,f2:text;

a:array[1..100]of integer;

i,n,t:integer;

begin

assign(f1,fi); reset(f1);

assign(f2,fo); rewrite(f2);

n:=0;

while not eoln(f1) do 

  begin

n:=n+1;

read(f1,a[n]);

end;

t:=0;

for i:=1 to n do 

  if a[i] mod 2=0 then t:=t+a[i];

writeln(f2,t);

close(f1);

close(f2);

end.

Đề thiếu rồi bạn

#include <bits/stdc++.h>

using namespace std;

long long i,a[100],n;

int main()

{

freopen("songuyen.txt","r",stdin);

n=20;

for (i=1; i<=n; i++) cin>>a[i];

for (i=1; i<=n; i++) cout<<a[i]<<" ";

return 0;

}

#include <bits/stdc++.h>
using namespace std;
unsigned long long a[1000],i,n,uc;
//chuongtrinhcon
unsigned long long ucln(long long a,long long b)
{
    if (b==0) return(a);
    else return(ucln(b,a%b));
}
//chuongtrinhchinh
int main()
{
    freopen("sn3.inp","r",stdin);
    freopen("uc.out","w",stdout);
    cin>>n;

for (i=1; i<=n; i++) cin>>a[i];

uc=ucln(a[1],a[2]);

for (i=3; i<=n; i++)

uc=ucln(uc,a[i]);

cout<<uc;
    return 0;
}