1.6.3 Do while Loops

The contents of a Do While loop is always executed at least once. Therefore the boolean variable isNotAnInteger need not be set to true. 

     * keep prompting for an integer until the user supplies one
     * using an input dialog box ,try/catch and a boolean variable
     * all with a while loop
    public int inputInteger(){
        String prompt, str;
        int num= 0;
        boolean isNotAnInteger;
        prompt = "Enter an integer:  ";
        do {
            str = JOptionPane.showInputDialog(prompt,null);
                num = Integer.parseInt(str);
                isNotAnInteger = false;
            catch(NumberFormatException e){
                 isNotAnInteger = true;
                 prompt = "You MUST enter an integer:  ";
        }while (isNotAnInteger);
        return num;