import javax.swing.JOptionPane;

public class test 
{
    public static void main( String[] args )
    {
        String input; //input string
        boolean done = false; //loop control variable
        int vowelCount = 0; //our vowel count
        
        //keep going until we're done
        while( !done )
        {
            //get input from the user
            input = JOptionPane.showInputDialog( "Enter a sentence:" );
            
            if( input == null || input.equals( "" ) )
            {
                //user canceled, or gave no input -- we are done
                done = true;
            }
            else
            {
                //convert all to lower case so we don't have to worry about upper vs lower case
                input = input.toLowerCase();
                for( int i = 0; i < input.length(); i++ )
                {
                    //check if it's a vowel
                    if( input.charAt( i ) == 'a' || input.charAt( i ) == 'e' 
                        || input.charAt( i ) == 'i' || input.charAt( i ) == 'o' 
                        || input.charAt( i ) == 'u' )
                    {
                        vowelCount++; //increment vowel count
                    }
                }
                
                //output results
                JOptionPane.showMessageDialog( null, "Vowel count: " + vowelCount + "\nVowel percentage: " + 
                        vowelCount * 100 / input.length() + "%", "Vowel Counter", JOptionPane.INFORMATION_MESSAGE );
            }
        }
    }
}