câu 1:

uses crt;
var s: string;
begin
clrscr;
write('nhap xau s: ');  readln(s);
write('xau sau khi chuyen sang in hoa: ',UPCASE(s));
readln;
end.

câu 2:

uses crt;
procedure nhapxuat;
var s: string;
begin

write('nhap xau s: ');  readln(s);
write('xau sau khi chuyen sang in hoa: ',UPCASE(s));
end;
begin
clrscr;
nhapxuat;

readln;

end.

câu 3:

uses crt;
var s: string;
f: text;
begin
clrscr;
assign(f, 'XauKQ.txt');
rewrite(f);
write('nhap xau s: ');  readln(s);
writeln(f, 'xau s ban dau: ', s);
writeln(f, 'xau s sau khi chuyen sang chu hoa: ',upcase(s));
close(f);
readln;
end.

1.

program phuongt;
uses crt;
  var s: string;
begin
         clrscr;
         write('Nhap xau s: '); readln(s);
         write('Chuyen sang chu hoa: ', upcase(s));
         readln
end.

2.

program phuongt;
uses crt;
procedure xau;
var s: string;
begin
         write('Nhap xau s: '); readln(s);
         write('Chuyen sang chu hoa: ', upcase(s));
end;
begin
        clrscr;
        xau;
end.

3.

program phuongt;
uses crt;
  var s: string;
        op: text;
begin
        clrscr;
        assign(op, 'E:\XauKQ.txt');
        rewrite(op);
        write('Nhap xau s: '); readln(s);
        writeln(op, 'Xau s: ', s);
        writeln(op, 'Xau s sau khi chuyen sang chu hoa: ', upcase(s));
        close(op);
        write('Mo file de xem ket qua');
        readln
end.