Question

用delphi写的 报错提示 undeclared identifier：'ShowMessage'这是为什么啊

program ecp;{$APPTYPE CONSOLE}uses
SysUtils;
var
R1,R2:double;
begin
{ TODO -oUser -cConsole Main : Insert code here }
while true do begin
try
write('enter a real number:');
readln(R1);
write('enter another real number:');
readln(R2);
writeln('the first number divided by the second is:',(R1/R2):5:3);
except
on EInOutError do
ShowMessage('it is not a valid number');
on EZeroDivide do
ShowMessage('can not divide by zero');
end;
end;
end.
报错提示 undeclared identifier：'ShowMessage'这是为什么啊

Answer 1

缺少：Dialogs单元在uses 后面加上Dialogs单元就行了。或者 Application.MessageBox('can not divide by zero', '', MB_OK + MB_ICONINFORMATION);

Answer 2

在uses后面加上 dialogs