1.用java实现了数据结构中表达式求值算法，进一步了解了类的继承
public class StringDemo{ public static void main(String args[])
{ char[] helloArray = { 'r', 'u', 'n', 'o', 'o', 'b'};
String helloString = new String(helloArray);
System.out.println( helloString );
}
