public class IsDigit
{
    public static void main(String[] args) 
    {
        char c;
        
        c = 52;
        System.out.println(c);

        c = '4';    // Change this and demo

        if ( 48 <= c && c <= 57 )
            System.out.println("Digit symbol");
        else
            System.out.println("Not a digit symbol");
        
        if ( '0' <= c && c <= '9' )
            System.out.println("Digit symbol");
        else
            System.out.println("Not a digit symbol");
        
        if ( Character.isDigit(c) )
            System.out.println("Digit symbol");
        else
            System.out.println("Not a digit symbol");
    }
}