1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
|
/*DListNode1*/
/* DListNode1.java */
public class DListNode1 {
public Object item;
// public short[][] colorVal;
public DListNode1 prev;
public DListNode1 next;
DListNode1() {
item = 0;
prev = null;
next = null;
}
DListNode1(Object i) {
item = i;
prev = null;
next = null;
}
}
//////////////
/* Double linked list */
public class DList1 {
protected DListNode1 head;
protected DListNode1 tail;
protected long size;
public DList1() {
head = null;
tail = null;
size = 0;
}
public DList1(Object a) {
head = new DListNode1();
tail = head;
head.item = a;
size = 1;
}
public DList1(Object a, Object b) {
head = new DListNode1();
head.item = a;
tail = new DListNode1();
tail.item = b;
head.next = tail;
tail.prev = head;
size = 2;
}
public void insertFront(Object i) {
DListNode1 temp = new DListNode1(i);
if (size == 0) {
head = temp;
tail = temp;
}
else {
temp.next = head;
head.prev = temp;
head = temp;
} size++;
}
public void removeFront() {
if (size == 0) {
return;
}
else if (size == 1) {
head = null;
tail = null;
size--;
}
else {
head = head.next;
head.prev = null;
size--;
}
}
public String toString() {
String result = "[ ";
DListNode1 current = head;
while (current != null) {
result = result + current.item + " ";
current = current.next;
}
return result + "]";
}
/////////////
public static void main(String[] args) {
DList1 l = new DList1();
l.insertFront(9);
if (l.head.item != 9) {
System.out.println("head.item is wrong.");
|
The line "if (l.head.item != 9" gave me the error it said something like object is not compatible with int. I am really confuse on why is that.
Last edited on
this should a) be in the lounge b) be in the proper forum. does head have the member item?
l.head.item, lets look at the classes of that construct: Dlist1.DListNode1.Object
Yeah, that's not an int...
You could either implement item as an int, or cast it to an int. Is there a reason you're using an Object class for item?