uses crt;

const fi='xau.txt'

var f1:text;

s:string;

i,d,kt:integer;

begin

clrscr;

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

readln(f1,s);

d:=length(s);

kt:=0;

for i:=1 to d do

if st[i]<>st[d-i+1] then kt:=1;

if kt=0 then writeln('Xau doi xung')

else writeln('Xau khong doi xung');

readln;

end.

#include <bits/stdc++.h>

using namespace std;

int main() {

freopen("VIRUS.INP","r",stdin);

freopen("VIRUS.OUT","w",stdout);

string S, R;

cin >> S >> R;

while(S.find(R) >= 0) {

int p = S.find(R);

if (p >= 0) S.erase(p,R.length());

else break;

}

cout<<S;

return 0;

}

Câu 1: 

uses crt;

var st:string;

d,i,dem:integer;

begin

clrscr;

write('Nhap xau:'); readln(st);

d:=length(st);

write('Xau sau khi xoa so la: ');

for i:=1 to d do 

  if not(st[i] in ['0'..'9']) then write(st[i]);

writeln;

dem:=0;

for i:=1 to d do 

  if st[i]=#32 then inc(dem);

writeln('Xau co ',dem,' dau cach');

writeln('Do dai cua xau la: ',d);

readln;

end. 

Câu 2: 

uses crt;

const fi='kq.out'

var st1,st2:string;

f1:text;

begin

clrscr;

write('Nhap xau thu 1:'); readln(st1);

write('Nhap xau thu 2:'); readln(st2);

assign(f1,fi); rewrite(f1);

if length(st2)>length(st1) then writeln(f1,st2)

else writeln(f1,st1);

close(f1);

end.

Câu 3: 

uses crt;

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

i,n,t,dem:integer;

begin

clrscr;

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

for i:=1 to n do 

  begin

write('A[',i,']='); readln(a[i]);

end;

t:=0;

dem:=0;

for i:=1 to n do 

  if a[i] mod 2=0 then

begin

t:=t+a[i];

inc(dem);

end;

writeln('Trung binh cong cac so chan la: ',t/dem:4:2);

readln;

end.

#include <bits/stdc++.h>

using namespace std;

string st;

int d,i;

int main()

{

cin>>st;

cout<<st<<endl;

d=st.length();

for (i=d-1; i>=0; i--) cout<<st[i];

cout<<endl;

for (i=0; i<d; i++) cout<<st[i]<<endl;

return 0;

}

const fi='input.txt'

fo='output.txt'

var f1,f2:text;

st:string[125];

a:array[1..125]of string;

i,d,dem,kt,j:integer;

begin

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

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

readln(f1,st);

d:=length(st);

dem:=1;

a[1]:=st[1];

for i:=1 to d do

  begin

kt:=0;

for j:=1 to dem do 

  if a[j]=st[i] then kt:=1;

if kt=0 then 

begin

inc(dem);

a[dem]:=st[i];

end;

end;

for i:=1 to dem do 

  begin

dem1:=0;

for j:=1 to d do 

if a[i]=st[j] then inc(dem1);

writeln(f2,a[i],' xuat hien ',dem1,' lan');

end;

close(f1);

close(f2);

end.

program bai1;
uses crt;
var i:integer;
s,s1:string;
begin
  clrscr;
  write('nhap S:');readln(s);
  while pos('C',s)<>0 do
  begin
    insert('LOP11A',s,pos('C',s));
    delete(s,pos('C',s),1);
  end;
  writeln('xau sau khi bien doi la: ',s);
  writeln('do dai cua xau tren la: ',length(s));
  write('nhap s1:');readln(s1);
  if s1[1]=s[1] then writeln('ki tu dau cua hai xau trung nhau')
  else writeln('ki tu dau cua hai xau khong trung nhau');
  readln;
end.