endflag:=0;
while(endflag=0) do begin
clrscr;
errorflag:=1;
while(errorflag=1) do begin
gotoxy(1,1);ClrEol;
write('please enter x distance ');
read(x);
gotoxy(1,3);ClrEol;
write('please enter y distance ');
read(y);
errorflag:=0;
if x<0 then begin
gotoxy(1,5);
write('I am sorry but both distances must be positive');
gotoxy(4,6);
write('You will have to reenter both x and y');
errorflag:=1;
end
else
if y<0 then begin
gotoxy(1,5);
write('I am sorry but the y distance must be positive');
gotoxy(4,6);
write('You will have to reenter both x and y');
errorflag:=1;
end;
end;
distance:=sqrt(x*x+y*y);
gotoxy(1,5);ClrEol;
write('the distance is ',distance:10:2);
gotoxy(4,6);
write('Do you want to enter more numbers; enter Y for yes, N for No ');
readln;
readln(answer);
if (answer='N') then begin
endflag:=1;
end;
end;
end.