câu 1:

uses crt;

var a: array[1..100] of integer;

i,n,s: integer;

begin

clrscr;

write ('nhap n: ');  readln (n);

s:=0;

for i:=1 to n do

begin

write ('nhap phan tu thu ',i,': ');  readln (a[i]);

if a[i] mod 3=0 then s:=s+a[i];

end;

writeln ('tong la: ',s);

readln;

end.

câu 2:

uses crt;

var s: string;

i,k: byte;

begin

clrscr;

write ('nhap xau: ');  readln (s);

for i:=1 to length(s) do

if s[i]=' ' then begin k:=i; break; end;

writeln ('vi tri ki tu trang dau tien la: s[',k,']');

readln;

end.

`text{#Trumtinhoc}`

`1)`

uses crt;
 var a:array[1..99] of longint;
 n,s,i:longint;
  begin
   clrscr;
    write('Nhap n:'); readln(n);
  for i:=1 to n do
   begin
 write('a[',i,']='); 
  readln(a[i]);
   if a[i] mod 3=0 
    then s:=s+a[i];
     end;
      writeln('S=',s);
       end.

$\\$$\\$$\\$$\\$

`2)`

uses crt;
 var a:string[150];
  begin
   clrscr;
    writeln('Nhap xau: ');
    readln(a);
    writeln('Vi tri dau tien co chua dau cac la: ',Pos(' ',a));
    end.

$\\$$\\$$\\$