begin i:=2; writeln (' Nhap so tu nhien n '); readln (n); if n < 2 then writeln ( n,' khong phai la so nguyen to'); if n = 2 then witeln ( n,' la so nguyen to'); if n > 2 then begin while i = n do if n mod i = 0 then begin writeln ( n,' khong phai la so nguyen to'); i:=n; end; else begin i:=i+1; if i = n do writeln ( n,' la so nguyen to ); end; end.
uses crt; var a,b,d,i:longint; function nt(a:longint):boolean; var i:longint; begin i:=2; while(a>1)and(a mod i<>0)do inc(i); nt:=i=a; end; begin clrscr; write('Nhap a: ');readln(a); write('Nhap b: ');readln(b); d:=0; for i:=a to b do if nt(i) then inc(d); writeln('Co ',d,' so nguyen to trong doan tu ',a,' den ',b); readln end.
