primefactor.pas

program primefactor;
uses crt;
var i, n, i2, i3: longint;
    prime: array [1..1000000] of longint;
    s, tmp: string;
function checkprime(n: longint): boolean;
 var i: longint;
 begin
  checkprime:=true;
  for i:=2 to n-1 do begin
   if n mod i=0 then begin
    checkprime:=false;
    break;
   end;
  end;
 end;
procedure findprime;
 var i, i2: longint;
 begin
  i2:=0;
  for i:=2 to n do begin
   if checkprime(i)=true then begin
    inc(i2);
    inc(i3);
    prime[i2]:=i;
   end;
  end;
 end;
begin
 clrscr;
 write('Nhap n: ');
 readln(n);
 findprime;
 i2:=1;
 while n<>1 do begin
  while n mod prime[i2]=0 do begin
   str(prime[i2], tmp);
   s:=s+tmp+'x';
   n:=n div prime[i2];
  end;
  inc(i2);
 end;
 delete(s, length(s), 1);
 write(s);
 readkey;
end.