Write a function called "odd" that takes a linked list and returns the odd-numbered elements. Actually, write two functions called "odd" and "even". odd(L) returns a list of the 1st,3rd,5th... items in L. even(L) returns a list of the 2nd,4th,6th... items in L. And each function calls the other. These two functions are based on a simple observation. L.next is like L, but with the first item missing. If we take away the first item, item N+1 becomes item N. So the 2nd,3rd,4th elements of L are the 1st,2nd,3rd elements of L.next. Now if N+1 is odd, N is even, while if N+1 is even N is odd. So the odd members of L.next are even members of L, and the even members of L.next are odd members of L. Then we can compute odd(L) as follows. If L is null return null. Otherwise return a list whose first item is L.item, while its tail is even(L.next). To compute even(L): If L is null return null. Otherwise return odd(L.next). Your main function should read a list of positive integers from the command line, with -1 terminating the list. It should form a linked list containing these integers, compute the list of odd members, and print them.
Possible Solution:
Compile two files in the same folder:
javac list.java
javac homework4.java
Then run: java homework4
1/ list.java
class list
{
public int first;
public list rest;
public list(int x, list y)
{
first = x;
rest = y;
}
}
{
public int first;
public list rest;
public list(int x, list y)
{
first = x;
rest = y;
}
}
2/ homework4.java
import java.util.Scanner;
public class homework4
{
public static void main(String[] args)
{
int n = 0;
list l = null, new_list = null;
// Create a scanner to read from keyboard
Scanner scanner = new Scanner (System.in);
while (n != -1)
{
System.out.println("enter a number: ");
n = scanner.nextInt();
if (n!= -1)
l = insert(n, l);
}
new_list = odd(l);
show_list(new_list);
System.out.println();
}
static list odd(list y)
{
if (y == null)
return null;
else
return new list(y.first, even(y.rest));
}
static list even(list y)
{
if (y == null)
return null;
else
return odd(y.rest);
}
static list insert(int x, list y)
{
list current = y;
if (y == null)
return new list(x, y);
else
{
while (current.rest != null)
current = current.rest;
current.rest = new list(x, null);
return y;
}
}
static void show_list(list y)
{
if(y != null)
{
System.out.print(y.first + " ");
show_list(y.rest);
}
}
}
