To be able to the Browxy community to help you effectively please follow this guidelines
a) Use a meaningful subject like "Java - Compilation Issue with Palindrome problem" or "Java - Issue using to static methods"
b) Explain clearly the problem
c) Paste your code URL in the post
1) Right Click on your project, select Edit Project Properties and uncheck the private checkbox (this is to allow anybody to see your program) and click "Save"
2) Right click on your project and click "Get Url", this will give you the URL to share your program
3) Paste the URL in the post
d) Paste your code in the post using code tags
- codeTagsButton.png (10.13 KiB) Viewed 38817 times
Also add the names of the files in bold before each one of them
e) Preview your post before posting to see If it is nice and well formatted
Example
Subject How to write then Main method for a Palindrome Problem
Description I want to print a list and determine if it is palindrome
I have 2 methods: printList & isPalindrome, but I don't know hot to execute them in the main
please help
Code Url http://www.beta.browxy.com#ALIEN_10640
IntList.java
Code: Select all
public class IntList{
private IntNode _head;
public IntList() {
_head = null;
}
public IntList (IntNode node){
_head = node;
}
public boolean isPalindrome(){
int len,count;
IntNode p,prev;
//No.1 - find the lists length
for(p = _head, len = 0; p != null; p= p.getNext() )
len++;
//list with one element is palindrom
if(len == 1) {
System.out.println("len = 1");
return true;
}
//No.2 - find the middle element in the list
//we use two pointers so we won't loose the end of the list.
p = _head;
prev = null ;
count = 0;
while(count < len/2)
{
prev = p;
p = p.getNext();
count++;
}
//now prev points to the last element in the first half
// p points to the middle element
//No.3 - seperate the two halfs
prev.setNext(null);
//No.4 - reverse the list that starts with p
//(we'll write a method that does it)
p = reverseList(p);
//No.5 - run from both sides and look for unmatched nums
IntNode first ,second ;
first = _head;
second = p;
while(first != null)
{
System.out.println("checking: " + first.getValue() + " against: " + second.getValue());
if(first.getValue() != second.getValue())
return false;
first = first.getNext();
second = second.getNext();
}
//if we arrived this line,the list is palindrome
return true;
}
/**
* Reverse the given list,and return its new head.
*/
private static IntNode reverseList(IntNode h){
//current represnts the element to be reversed
//rev is the reversed list's head
IntNode current,rev;
current = h;
rev = null ;
while(h != null)
{
h = h.getNext();
current.setNext(rev);
rev = current ;
current = h;
}
return rev;
}
public void printList(){
IntNode temp = _head;
while(temp != null)
{
System.out.print(temp.getValue() + " --> ");
temp = temp.getNext();
}
System.out.println(" null");
}
}
Code: Select all
public class IntNode {
private int _value;
private IntNode _next;
public IntNode(int val , IntNode n){
_value = val;
_next = n;
}
public int getValue(){
return _value;
}
public IntNode getNext(){
return _next;
}
public void setValue(int v){
_value = v;
}
public void setNext(IntNode node){
_next = node;
}
}