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1
8
9 class List {
10
11 Cell head = null;
12
13 void add(Object  e) {
14 head = new Cell(e,head);
15 }
16
17 Iterator iterator() {
18 return new ListItr(head);
19 }
20 }
21
22 class Cell {
23
24 Object data;
25 Cell next;
26
27 Cell(Object d, Cell n) {
28 data = d;
29 next = n;
30 }
31 }
32
33 interface Iterator {
34 boolean hasNext();
35 Object next();
36 }
37
38 class ListItr implements Iterator {
39
40 Cell cell;
41
42 ListItr(Cell head) {
43 cell = head;
44 }
45
46 public boolean hasNext() {
47 return cell != null;
48 }
49
50 public Object next() {
51 Object result = cell.data;
52 cell = cell.next;
53 return result;
54 }
55 }
56
57 class Point {
58
59 float x,y;
60
61 Point(float x,float y) {
62 this.x = x;
63 this.y = y;
64 }
65
66 void flip() {
67 float t = x;
68 x = y;
69 y = t;
70 }
71
72 void print() {
73 System.out.print("("+x+","+y+")");
74 }
75 }
76
77 public class PurityTest {
78
79 static float sumX(List list) {
80 float s = 0;
81 Iterator it = list.iterator();
82 while (it.hasNext()) {
83 Point p = (Point) it.next();
84 s += p.x;
85 }
86 return s;
87 }
88
89 static void flipAll(List list) {
90 Iterator it = list.iterator();
91 while (it.hasNext()) {
92 Point p = (Point) it.next();
93 p.flip();
94 }
95 }
96
97 static void print(List list) {
98 Iterator it = list.iterator();
99 System.out.print("[");
100 while (it.hasNext()) {
101 Point p = (Point) it.next();
102 p.print();
103 if (it.hasNext()) System.out.print(";");
104 }
105 System.out.println("]");
106 }
107
108 public static void main(String args[]) {
109 List list = new List();
110 list.add(new Point(1,2));
111 list.add(new Point(2,3));
112 list.add(new Point(3,4));
113 print(list);
114 System.out.println("sum="+sumX(list));
115 sumX(list);
116 print(list);
117 flipAll(list);
118 print(list);
119 }
120 }
121 |
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Java API By Example, From Geeks To Geeks.