Chương trình:

program bai_10_chuong_4;

uses crt;

var

s: string[100];

i, dem: integer;

Begin

clrscr;

write('Nhap xau vao:'); readln(s); dem:= 0;

for i:= 1 to length(s) do

if ('0'<=s[i]) and(s[i]<=’9') then dem:=dem+l;

Writeln('Trong xau s co '»dem,' chu so thap phan');

readln;

End.

uses crt;

var st:string;

i,d,dem:integer;

begin

clrscr;

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

d:=length(st);

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

dem:=0;

for i:=1 to d do 

  if st[i] in ['0'..'9'] then inc(dem);

writeln(dem);

readln;

end.

uses crt;

var st:string;

i,d:integer;

begin

clrscr;

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

d:=length(st);

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

for i:=1 to d do 

  if st[i]=#32 then delete(st,i,1);

writeln('Xau moi la: ',st);

readln;

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,s:string;

    i,d,dem,kt,j,dem1:integer;

begin

clrscr;

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

writeln('Xau vua nhap la: ',s);

d:=length(s);

for i:=1 to d do

  if s[i]=#32 then delete(s,i,1);

dem:=1;

st[1]:=s[1];

for i:=1 to d do

  begin

     kt:=0;

     for j:=1 to dem do

       if s[i]=st[j] then kt:=1;

     if kt=0 then

        begin

           inc(dem);

           st[dem]:=s[i];

        end;

  end;

for i:=1 to dem do

  begin

     dem1:=0;

     for j:=1 to d do

       if st[i]=s[j] then inc(dem1);

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

  end;

readln;

end.

uses crt;

var st:string;

i,d:integer;

begin

clrscr;

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

d:=length(st);

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

for i:=1 to d do 

  if st[i] in ['a'..'z'] then upcase(st[i]);

writeln(st);

readln;

end.

program bai_10_chuong_4;

uses crt;

var

s: string[100];

i, dem: integer;

Begin

clrscr;

write('Nhap xau vao:'); readln(s); dem:= 0;

for i:= 1 to length(s) do

if ('0'<=s[i]) and(s[i]<=’9') then dem:=dem+l;

Writeln('Trong xau s co '»dem,' chu so thap phan');

readln;

End.

uses crt;

var st:string[100];

i,d,kt:integer;

begin

clrscr;

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

kt:=0;

for i:=1 to length(st) do

if st[i]<>st[length(st)-i+1] then kt:=1;

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

else writeln('Xau khong doi xung');

readln;

end.

 Cậu tham khảo nhé!!!

https://hoc24.vn/cau-hoi/viet-chuong-trinh-nhap-mot-xau-tu-ban-phim-thay-ky-tu-39a39-thanh-39i39-va-in-xau-da-thay-ra-man-hinh-thay-tat-ca-chu-39anh39-t.257698320219

uses crt;

var s:string;

begin

clrscr;

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

while pos('a',s)<>0 do

begin

insert('i',s,pos('a',s));

delete(s,pos('a',s),1);

end;

write('Xau sau khi chuyen la : ',s);

readln;

end.

Program HOC24;

var s: string;

i: byte;

begin

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

for i:=1 to length(s) do if s[i]<>'a' then write(s[i]);

readln

end.

uses crt;

var st:string;

i,d:integer;

begin

clrscr;

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

d:=length(st);

for i:=1 to d do 

 if st[i]='a' then delete(st,i,1);

writeln(st);

readln;

end.