I have a program that reads a file and then creates objects from the contents of
ID: 3587063 • Letter: I
Question
I have a program that reads a file and then creates objects from the contents of the file. How can I create a linked list of objects and use it with the package class instead of creating and using an array of objects? I am not allowed to use any arrays of objects or any java.util. lists in this program.
Runner class:
import java.util.Scanner;
import java.io.*;
class Runner {
public static Package[] readFile() {
try {
File f = new File("input.txt");
Scanner sc = new Scanner(f);
double l, h, w;
int count = 0;
while(sc.hasNext()){
l = sc.nextDouble();
h = sc.nextDouble();
w = sc.nextDouble();
sc.nextLine();
count++;
}
}
}
catch (Exception e){
e.printStackTrace();
}
return array;
}
public static void getLargestPack(Package[] array) {
//finding largest package
Package maxp = array[0];
int maxpind = 0;
for(int i = 1; i < array.length; i++){
if(array[i].getVolume() > maxp.getVolume()) {
maxp = array[i];
maxpind = i;
}
}
System.out.println("index of largest package is " + maxpind);
maxp.printDimensions();
System.out.println("Volume: "+maxp.getVolume());
}
public static void main (String[] args) throws java.lang.Exception {
node newN = null;
node head = null;
node current = null;
Package[] array = readFile();
getLargestPack(array);
LinkedList = new LinkedList(
//cubic and non cubic packages
int c = 0, nc = 0;
for(int i = 0; i < array.length; i++){
if(array[i].isCube()) c++;
else nc++;
}
System.out.println("number of cubic packages are: " + c);
System.out.println("number of non cubic packages are: " + nc);
//details of cubic packages
float sum_vol = 0;
for(int i = 0; i < array.length; i++){
if(array[i].isCube()){
array[i].printDimensions();
sum_vol += array[i].getVolume();
}
}
System.out.println("average volume is: " + sum_vol/c);
}
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
Package Class:
import java.util.*;
import java.lang.*;
import java.io.*;
class Package{
private double l, h, w;
public Box (double l, double h, double w, int ) {
this.l = l;
this.h = h;
this.w = w;
}
public boolean isCube() {
return l == h && h == w;
}
public double getVolume() {
return l * w * h;
}
public void printDimensions() {
System.out.println("Dimensions in length, height, width: " + l + ", " + h + ", " + w);
}
}
Explanation / Answer
Please find the below code without using util pacakge.
Runner.class
package com.list;
import java.util.Scanner;
import java.io.*;
class Runner {
public static void readFile() {
try {
}
catch (Exception e){
e.printStackTrace();
}
//return array;
}
public static void main (String[] args) throws java.lang.Exception {
/*node newN = null;
node head = null;
node current = null;*/
LinkedList Llist = new LinkedList();
File f = new File("C:/Santhosh/input.txt");
Scanner sc = new Scanner(f);
double l, h, w;
int count = 0;
while(sc.hasNext()){
l = sc.nextDouble();
h = sc.nextDouble();
w = sc.nextDouble();
Package p = new Package(l, h, w);
DataItems data = new DataItems(count,p);
Llist.insertNode(data);
//sc.nextLine();
count++;
}
Llist.displayList();
//readFile();
Llist.getLargestPack();
//LinkedList = new LinkedList(
Llist.cubic();
}
}
Package.java
package com.list;
import java.util.Scanner;
import java.io.*;
class Runner {
public static void readFile() {
try {
}
catch (Exception e){
e.printStackTrace();
}
//return array;
}
public static void main (String[] args) throws java.lang.Exception {
/*node newN = null;
node head = null;
node current = null;*/
LinkedList Llist = new LinkedList();
File f = new File("C:/Santhosh/input.txt");
Scanner sc = new Scanner(f);
double l, h, w;
int count = 0;
while(sc.hasNext()){
l = sc.nextDouble();
h = sc.nextDouble();
w = sc.nextDouble();
Package p = new Package(l, h, w);
DataItems data = new DataItems(count,p);
Llist.insertNode(data);
//sc.nextLine();
count++;
}
Llist.displayList();
//readFile();
Llist.getLargestPack();
//LinkedList = new LinkedList(
Llist.cubic();
}
}
Node.java
package com.list;
public class Node{
// immutable class representing head node of linked list
private DataItems dataItems;
private Node nextNode;
public void setNextNode(Node _nextNode){
this.nextNode=_nextNode;
}
public Node getNextNode(){
return nextNode;
}
public DataItems getDataItems(){
return dataItems;
}
public void setDataItems(DataItems _dataItems){
this.dataItems=_dataItems;
}
}
HeadNode.java
package com.list;
public class HeadNode{
// immutable class representing head node of linked list
Node nextNode;
public void setNextNode(Node _nextNode) {
nextNode=_nextNode;
}
public Node getNextNode() {
return nextNode;
}
}
DataItems.java
package com.list;
public class DataItems{
private int key;
private Package p;
public DataItems(int _key, Package p){
this.key=_key;
this.p=p;
}
public int getKey() {
return key;
}
public Package getP() {
return p;
}
public String toString() {
return "("+getKey()+","+getP()+")";
}
}
LinkedList.java
package com.list;
public class LinkedList{
HeadNode head;
public LinkedList(){
head = new HeadNode();
}
// insert node at the beginning of the list
public void insertNode(DataItems _data){
Node newNode = new Node();
newNode.setDataItems(_data);
Node nextNode = head.getNextNode();
head.setNextNode(newNode);
newNode.setNextNode(nextNode);
}
// delete node at the beginning of the list
public void deleteNode(){
Node toBeDeletedNode = head.getNextNode();
if(toBeDeletedNode!=null) {
Node nextNode = toBeDeletedNode.getNextNode();
head.setNextNode(nextNode);
toBeDeletedNode.setNextNode(null);
} else {
System.out.println("No nodes to be deleted");
}
}
// display all nodes data
public void displayList(){
Node nodes = head.getNextNode();
int i=0;
while(nodes!=null) {
DataItems data = nodes.getDataItems();
System.out.println("Node "+i+" : "+data.toString());
nodes = nodes.getNextNode();
i++;
}
}
// reverse order of linked list
public void reverseLinkedList(){
int sizeOfList = size();
Node lastNode = nodeAtIndex(sizeOfList-1);
Node snode, tnode;
for(int i=sizeOfList-2;i>=0;i--){
snode = nodeAtIndex(i);
tnode = snode.getNextNode();
tnode.setNextNode(snode);
}
nodeAtIndex(0).setNextNode(null);
head.setNextNode(lastNode);
}
// reverse order of linked list
public void searchKey(int _key){
int i=0;
DataItems data = dataAtNodeIndex(i);
while(data!=null){
if(data.getKey()== _key){
System.out.println("Node at index : "+i+" has data item : "+data.toString());
}
i++;
data = dataAtNodeIndex(i);
}
}
// insert a node at index
public void insertNodeAtIndex(int _index, DataItems _data){
Node newNode = new Node();
newNode.setDataItems(_data);
if(_index==0) {
insertNode(_data);
} else {
Node prevNode = nodeAtIndex(_index-1);
if(prevNode!=null) {
Node nextNode = prevNode.getNextNode();
newNode.setNextNode(nextNode);
prevNode.setNextNode(newNode);
}
}
}
// delete a node at index
public void deleteNodeAtIndex(int _index){
if(_index==0) {
deleteNode();
} else {
Node prevNode = nodeAtIndex(_index-1);
if(prevNode!=null) {
Node targetNode = prevNode.getNextNode();
Node nextNode = targetNode.getNextNode();
targetNode.setNextNode(null);
prevNode.setNextNode(nextNode);
}
}
}
// return data item at particular node
public DataItems dataAtNodeIndex(int _index){
Node nodes = nodeAtIndex(_index);
if(nodes!=null) {
return nodes.getDataItems();
} else {
return null;
}
}
// return node at particular index
private Node nodeAtIndex(int _index){
if(_index<0) {
return null;
} else {
Node nodes = head.getNextNode();
int i=0;
while(i<_index && nodes!=null) {
nodes = nodes.getNextNode();
i++;
}
return nodes;
}
}
// return the size of linked list
public int size() {
int count=0;
Node nodes = nodeAtIndex(count);
while(nodes!=null) {
nodes = nodeAtIndex(++count);
}
return count;
}
public Package getData(){
Node nodes = head.getNextNode();
DataItems data = nodes.getDataItems();
return data.getP();
}
public void getLargestPack() {
//finding largest package
Node nodes = head.getNextNode();
DataItems data = nodes.getDataItems();
Package maxp = data.getP();
int maxpind = 0;
int i=0;
while(nodes!=null) {
data = nodes.getDataItems();
//System.out.println("Node "+i+" : "+data.toString());
Package p1 = data.getP();
if(p1.getVolume() > maxp.getVolume()) {
maxp = p1;
maxpind = i;
}
nodes = nodes.getNextNode();
i++;
}
System.out.println("index of largest package is " + maxpind);
maxp.printDimensions();
System.out.println("Volume: "+maxp.getVolume());
}
public void cubic(){
//cubic and non cubic packages
int c = 0, nc = 0;
int i=0;
Node nodes = head.getNextNode();
float sum_vol = 0;
while(nodes!=null) {
DataItems data = nodes.getDataItems();
//System.out.println("Node "+i+" : "+data.toString());
Package p1 = data.getP();
p1.printDimensions();
if(p1.isCube()) {
c++;
//p1.printDimensions();
sum_vol += p1.getVolume();
}
else nc++;
nodes = nodes.getNextNode();
i++;
}
System.out.println("number of cubic packages are: " + c);
System.out.println("number of non cubic packages are: " + nc);
System.out.println("average volume is: " + sum_vol/c);
}
}
Thank you .............all the best.....
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