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 st[i]:='_';

writeln('Xau thay the la: ',st);

readln;

end.

hi nha mk tên là ngọc 6a. muốn hỏi nội

 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 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.

uses crt;

var st:string;

i,d:integer;

begin

clrscr;

readln(st);

d:=length(st);

for i:=1 to d do 

  if (st[i]<>'a') and (st[i]<>'A') then write(st[i]);

readln;

end.

uses crt;
var n,a,b,q:integer;
begin
clrscr;
write('n='); readln(n);
for a:=1 to n do
for b:=a to n do
if trunc(sqrt(sqr(a)+sqr(b)))=sqrt(sqr(a)+sqr(b)) then writeln(a,' ',b);
readln;
end.