Uses Crt;

Var St:String;

dem: Array[‘A’..’Z’] Of Byte;

i:Byte;

ch:Char;

Begin

Write(‘Nhap xau St: ‘); Readln(St);

{Khởi tạo mảng}

For ch:=’A’ To ‘Z’ Do dem[ch]:=0;

{Duyệt xâu}

For i:=1 To Length(St) Do

If Upcase(St[i]) IN [‘A’..’Z’] Then Inc(dem[Upcase(St[i])]);

{Liệt kê các ký tự ra màn hình}

For ch:=’A’ To ‘Z’ Do

If dem[ch]>0 Then Writeln(ch,’ : ’,dem[ch]);

Readln;

uses crt;

var st:string;

begin

clrscr;

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

writeln(length(st));

readln;

end.

Program HOC24;

var s: string;

x: char;

d: byte;

begin

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

write('Nhap ki tu: '); readln(x);

d:=0;

for i:=1 to length(s) do if s[i]=x then d:=d+1;

if d=0 then write('Ki tu do khong xuat hien trong xau') else write('Ki tu do xuat hien trong xau');

readln

end.

Cô ơi, cô chưa khai báo biến i thưa cô

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.

Use crt;

Var S : String;

P: longint;

Begin

Write('Nhap s: '); readln (S);

For P:=length(S) downto 1 do

Write(P);

Readln;

End.

uses crt;

var st:string;

i,d:integer;

begin

clrscr;

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

d:=length(st);

writeln('Xau ban vua nhap la: ',st);

writeln('Xau nguoc la: ');

for i:=d downto 1 do

write(st[i]:4);

readln;

end.

uses crt;

var st:string;

n,vt,d,i:integer;

begin

clrscr;

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

d:=length(st);

write('Nhap vi tri can xoa:'); readln(vt);

write('Nhap so ki tu can xoa:'); readln(n);

delete(st,vt,n);

writeln('Xau sau khi xoa la: ',st);

readln;

end.

#include <bits/stdc++.h>

using namespace std;

string st1,st2;

int d1,d2;

int main()

{

cin>>st1>>st2;

d1=st1.length();

d2=st2.length();

if (d1<d2) cout<<st1;

else cout<<st2;

return 0;

}

Program HOC24;

var i,d: byte;

s: string;

begin

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

d:=0;

for i:=1 to length(s) do if s[i] in ['0'..'9'] then d:=d+1;

write('Co ',d,' ki tu so trong xau');

readln

end.