uses crt;
var i,n,s,d: integer;
a: array[1..1000] of integer;
begin d:=0; clrscr;
write('Nhap so phan tu trong mang: '); readln(n);
for i:=1 to n do begin
  write('a[',i,']='); readln(a[i]); end;
for i:=1 to n do
  if not odd(i) and odd(a[i]) then begin
  s:=s+a[i]; inc(d); end;
writeln('S= ',s);
writeln('So phan tu thoa man: ',d);
readln;
end.

Mong câu tl hay nhất!

uses crt;
var a:array[1..1000000] of longint;
        n,i,s:longint;
begin
        clrscr;
        write('Nhap so luong phan tu: '); readln(n);
        for i:=1 to n do 
                begin
                        write('a[',i,']: '); readln(a[i]);
                        if (i mod 2=0) and (a[i] mod 2=1) then inc(s,a[i]);
                end;
        writeln('Tong cac so le o vi tri chan: ',s);
        readln;
end.