class Foo
{
public static void main(String[] sgf)
{
StringBuffer a = new StringBuffer("A");
StringBuffer b = new StringBuffer("B");
operate(a,b);
System.out.println(a+","+b);
}
static void operate(StringBuffer x,StringBuffer y)
{
x.append(y);
}}
//输入的结果如何才能变成AB,AB
//而不是AB,B |