program sapxep;
uses crt;
var a:array[1..100] of integer;
     i,j,tg,n:integer;
begin
clrscr;
write('Nhap so phan tu mang: ');readln(n);
if (n<0) then 
begin
writeln('So nhap vao khong thoa man.');
write('Moi nhap lai: ');readln(n);
end;
for i:=1 to n do
begin
write('Nhap a[',i,']: ');
readln(a[i]);
end;
writeln('Mang vua nhap: ');
for i:=1 to n do 
write(a[i],'  ');
writeln;
for i:=1 to n-1 do
     for j:=i+1 to n do 
     if (a[i] < a[j] ) then 
     begin 
     tg:=a[i];
     a[i]:=a[j];
     a[j]:=tg;
     end;
writeln('Mang sau khi sap xep: ');
for i:=1 to n do
write(a[i],'  ');
readln;
end.

//sai thì ib chữa cho