numberformatexception

[Wild Heart]

try
{
num = Integer.parseInt(JOptionPane.showInputDialog("Enter a number"));
}

catch(NumberFormatException nfe)
{
System.out.println("Sorry. You need to enter a number");
}

if user enters a number, all goes well. if not, that statement will b printed. now, this happens only once. i want it to happen repeatedly. so i thought of including a do while loop but it didnt work. it kept repeatedly asking me to enter a number. here's the code:-

do
{
try
{
num = Integer.parseInt(JOptionPane.showInputDialog("Enter a number"));
}

catch(NumberFormatException nfe)
{
System.out.println("Sorry. You need to enter a number");
flag = false;
}
}
while(!flag);

if i removed the !, it still wont work. i believe it works only the first time. but then since flag becomes false, it'll keep asking me no matter what i enter.
help plz
thanx

[Drain]

Ok so.. set it to true at the beginning of every loop.

[Wild Heart]

it worked!!!
thanx a lot man!