

Trình còn kém nên không được chuyên nghiệp về code lắm!
Mã:
program example;
uses crt;
var a,b,dapAn,d : Real;
c : char;
begin
clrscr;
write('Viet so dau tien : ');
readln(a);
write('Chon phep tinh (+,-,x, : ) = ');
readln(c);
write('Viet so tiep theo : ');
readln(b);
case c of
'+' : begin
writeln('Dap an : ',a+b:4:2);
end;
'-' : begin
writeln('Dap an : ',a-b:4:2);
end;
'x' : begin
writeln('Dap an : ',a*b:4:2);
end;
':' : begin
writeln('Dap an : ',a/b:4:2);
end;
end;
Repeat
write('Hay nhap mot con so : ');
readln(a);
write('Chon phep tinh (+,-,x, : ) = ');
readln(c);
write('Viet con so tiep theo : ');
readln(d);
case c of
'+' : begin
dapAn := a+d;
writeln('Dap an : ',dapAn:4:2);
end;
'-' : begin
dapAn := a-d;
writeln('Dap an : ',dapAn:4:2);
end;
'x' : begin
dapAn := a*d;
writeln('Dap an : ',dapAn:4:2);
end;
':' : begin
dapAn := a/d;
writeln('Dap an : ',dapAn:4:2);
end;
end;
until dapAn = 900000000;
readln;
end.