Question

我正在尝试编写一个简单的代码，用于交换Vector中的元素（方法中还有其他不相关的行用于其他目的，所以请忽略它们）。但是，当我调用Collections.swap（clone1,6,3）时，它会更改＆＃34; v＆＃34;矢量以及!!我做错了什么？

方法：

public static String DFS(Vector v){

            Vector clone1 = new Vector();
            clone1 = v;
            Vector clone2 = new Vector();
            clone2 = v;


            // In order to compare goal is reached or not I created a goal vector
            Vector solution = new Vector(9,0);
            for(int i = 0; i < 9; i++)
                    solution.addElement(i);


            if(v.isEmpty()){
                    return "Empty!!";
            }
            if(v.equals(solution)){
                    return "Solution!!!";
            }

            // In order to determine where the blank is
            int indexOfZero = 0;

            // Since this Depth-First Search, I am using stack as frontier
            Stack s = new Stack();


            indexOfZero = v.indexOf('0');

            if (indexOfZero == 6){
                            Collections.swap(clone1,6,3);
                            Collections.swap(clone2,6,7);
            }

            //for(int i = 0; i < list.size(); i++){
            //      s.push(list.get(i));
            //      System.out.println("Stack in for loop");
            //}

            //Vector a = (Vector)s.pop();
            System.out.println("\nElements after DFS:");
                    System.out.println(v.toString());
                    System.out.print("THIS IS MY ClONE 1: ");
                    System.out.println(clone1.toString());
                    System.out.print("THIS IS MY ClONE 2: ");
                    System.out.println(clone2.toString());
            System.out.println();
            return "a";
    }

Answer 1

您声明引用clone1和clone2引用与v相同的对象（并放弃了刚创建的new Vector()）。

将赋值运算符=与对象一起使用不会克隆该对象;它只是引用另一个引用来引用同一个对象。

v ----> Vector object
         ^
clone1 --+

您可以通过

创建Vector的副本

Vector clone1 = new Vector(v);

...视觉

v ----> Vector object

clone1 ----> Cloned Vector object

java中的Collections.swap（）交换方法中的所有内容

1 个答案: