program stringManipulation;

var
  st1, st2: string;
  countN, i: integer;

begin
  write('Nhap vao xau ki tu st1: ');
  readln(st1);
  countN := 0;
  for i := 1 to length(st1) do
  begin
    if (st1[i] = 'N') or (st1[i] = 'n') then
    begin
      countN := countN + 1;
    end;
  end;
  writeln('So ky tu N va n trong xau st1 la: ', countN);
  st2 := ''
  for i := 1 to length(st1) do
  begin
    if (st1[i] >= 'A') and (st1[i] <= 'Z') then
    begin
      st2 := st2 + st1[i];
    end;
  end;
  writeln('Cac ky tu in hoa trong xau st1 la: ', st2);
  write('Xau st1 viet theo chieu nguoc lai la: ');
  for i := length(st1) downto 1 do
  begin
    write(st1[i]);
  end;
  readln;
end.

st1 = input("Nhập vào xâu kí tự: ")
count_n = 0
st2 = ""
for char in st1:
    if char == 'N' or char == 'n':
        count_n += 1
    if char.isupper():
        st2 += char

print("Số lần xuất hiện của kí tự 'N' và 'n' là:", count_n)
print("Xâu kí tự chỉ chứa kí tự in hoa là:", st2)
print("Xâu kí tự đảo ngược là:", st1[::-1])

Giúp mk với mai mk phải nộp r

Program HOC24;

var s: string;

i,d: byte;

begin

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

d:=0;

for i:=1 to length(s) do if (s[i]='b') or (s[i]='B') then d:=d+1;

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

readln

end.

Program HOC24;

var i,d1,d2: byte;

st1,st2: string[60];

begin

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

//---------------Câu 1-------------------

d1:=0; d2:=0;

for i:=1 to length(st1) do

begin

if st1[i]='A' then d1:=d1+1;

if st1[i]='a' then d2:=d2+1;

end;

writeln('Co ',d1,' ki tu A trong xau');

writeln('Co ',d2,' ki tu a trong xau');

//---------------------- Câu 2 --------------------

st2:=''

for i:=1 to length(st1) do if st1[i] in ['a'..'z'] then st2:=st2+st1[i];

writeln('Xau st2 la: ',st2);

//------------------------------Câu 3--------------------

for i:=1 to length(st1) do st1[i]:=upcase(st1[i]);

write('Xau st1 sau khi in hoa la: ',st1);

//--------------------------------------------------------

readln

end.

uses crt;

var st:string;

begin

clrscr;

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

writeln(length(st));

readln;

end.

uses crt;

var a,b:string;

i,d:integer;

begin

clrscr;

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

d:=length(a);

b:=''

for i:=1 to d do 

  if a[i] in ['A'..'Z'] then b:=b+a[i];

writeln(b);

readln;

end.

uses crt;

var st:string;

dem,i,d:integer;

begin

clrscr;

readln(st);

dem:=0;

d:=length(st);

for i:=1 to d do

if st[i]=' ' then inc(dem);

write(dem);

readln;

end.

uses crt;

var st:string;

a:array[1..255]of string;

i,d,dem,kt,j,dem1:integer;

begin

clrscr;

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

d:=length(st);

a[1]:=st[1];

dem:=1;

for i:=1 to d do 

  begin

kt:=0;

for j:=1 to dem do 

  if st[i]=a[j] 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(a[i],' xuat hien ',dem1,' lan');

end;

readln;

end.

uses crt;

var a:string;

     c:char;

     i,dem:integer;

begin

    clrscr;

    readln(a);

    readln(c);

    dem:=0;

    for i:=1 to length(a) do

    if a[i]=c then dem:=dem+1;

    writeln(dem);

    readln;

end.

uses crt;

var st:string[50];

d,i:integer;

begin

clrscr;

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

d:=length(st);

for i:=1 to d do 

  if st[i] in ['a'..'z'] then write(st[i]:4);

readln;

end.