Câu 1:
program dem_A;
uses crt;
var s:string;
i,d:byte;
begin
clrscr;
write('Nhap xau: '); readln(s);
d:=0;
for i:=1 to length(s) do
if s[i]='A' then d:=d+1;
write('Co ',d,' ki tu A');
readln;
end.
Câu 2:
program trung_binh;
uses crt;
var f:text;
a,b:integer;
begin
clrscr;
Assign(f,'Dulieu.inp'); reset(f);
readln(f,a,b);
writeln('Trung binh cong la: ',(a+b)/2:0:2);
writeln('Trung binh nhan la: ',a*b/2:0:2);
readln;
end.