IN JAVA!!! package algs11; import java.text.DecimalFormat; import stdlib.*; publ
ID: 3595566 • Letter: I
Question
IN JAVA!!!
package algs11;
import java.text.DecimalFormat;
import stdlib.*;
public class CSC300Program4 {
// this class maintains a linked structure via the instance variable first
/*
* CSC300Program4 version 1.1
* fixed format specifier in function:
* testPositionOfFirstOccurence
*
*
* Does your program have compile errors? Yes / No
* Which TODOs have been completed correctly? Delete the lines below for TODOs that are NOT correct
* TODO 1
* TODO 2
* TODO 3
* TODO 4
* TODO 5
*
* Complete the methods below.
* None of the methods should modify the list, unless that is the purpose of the method.
*
* You may not add any fields to the node or list classes.
* You may not add any methods to the node class.
*
* You MAY add private methods to the CSC300Program4 class (helper functions for the recursion).
*/
static boolean showMeSuccess = false; // set to true to also see Success notifications for tests
// set to false to only see Failure notifications for tests
static class Node {
public Node (double item, Node next) { this.item = item; this.next = next; }
public double item;
public Node next;
}
Node first;
// a function to compute the size of the list, using a loop
// an empty list has size 0
public int sizeIterative () {
return StdRandom.uniform (100); //TODO 1: fix this
}
// a function to compute the size of the list using recursion
// empty list has size 0
// You will want to create a helper function to do the recursion
public int sizeRecursive () {
return StdRandom.uniform (100); //TODO 2: fix this
}
// a function to compute the position of the first occurrence of NUM in the list,
// where NUM is passed as a parameter
// and positions are counted as an offset from the beginning.
//
// if NUM is 5.0 and 5.0 is the FIRST element, the position is 0
// if NUM is 5.0 and it does not appear, return -1
//
// you can write this iteratively or recursively, but you should only have one loop or recursive helper
// I would expect
// [0,1,2,5,5,5,5,5,8,9].positionOfFirstNumFromBeginning(5) == 3
// [0,1,3,4,5,5,2,5,8,9].positionOfFirstNumFromBeginning(2) == 6
public int positionOfFirstNumOccurrence (double num) {
return StdRandom.uniform (100); //TODO 3: fix this
}
// return the second-to-last value in the list,
// Precondition: the list has at least 2 values
// you can write this iteratively or recursively, but you should only have one loop or recursive helper
// you may not call any other method (e.g. size )
//
// [0,1,2,5,5,5,5,5,8,9].secondToLastValue() == 8
// [0,1].secondToLastValue() == 0
public double secondToLastValue ( ) {
return StdRandom.uniform (100); //TODO 4: fix this
}
// a function to delete the second node if it exists, if not, the list is unchanged
// [0,1,2,8,9].deleteSecondIfPossible() --> [0,2,8,9]
// [0,9].deleteSecondIfPossible() --> [0]
// [].deleteSecondIfPossible() --> []
public void deleteSecondIfPossible () {
// TODO 5: fix this
}
// for debugging purposes, you may comment/uncomment the two calls in main below
// you should restore the calls as below when you submit your solution
public static void main (String args[]) {
//mainDebug ();
mainRunTests ();
}
private static void mainDebug () {
// Use this for debugging!
// Add the names of helper functions if you use them.
Trace.drawStepsOfMethod ("sizeIterative");
Trace.drawStepsOfMethod ("sizeRecursive");
Trace.drawStepsOfMethod ("positionOfFirstNumOccurrence");
Trace.drawStepsOfMethod ("secondToLastValue");
Trace.drawStepsOfMethod ("deleteSecondIfPossible");
Trace.run ();
// To Use: Put the test here you want to debug:
testSizeIterative (4, "11 -21.2 31 41");
}
private static void mainRunTests () {
testSizeIterative (0, "");
testSizeIterative (1, "11");
testSizeIterative (2, "11 21");
testSizeIterative (4, "11 -21.2 31 41");
testSizeRecursive (0, "");
testSizeRecursive (1, "11");
testSizeRecursive (2, "11 21");
testSizeRecursive (4, "11 -21.2 31 41");
testPositionOfFirstNumOccurrence (-1, 99, "");
testPositionOfFirstNumOccurrence (-1, 99, "11");
testPositionOfFirstNumOccurrence (-1, 99, "11 21 31 41");
testPositionOfFirstNumOccurrence (0, 11, "11 21 31 41");
testPositionOfFirstNumOccurrence (3, 11, "5 21 31 11");
testPositionOfFirstNumOccurrence (0, 11, "11 11 11 11 11");
testPositionOfFirstNumOccurrence (2, 31, "11 21 31 31 41");
testSecondToLastValue (31, "11 21 31 41");
testSecondToLastValue (21, "11 21 31");
testSecondToLastValue (11, "11 21");
testDeleteSecondIfPossible ("[ ]", "");
testDeleteSecondIfPossible ("[ 11 ]", "11");
testDeleteSecondIfPossible ("[ 11 ]", "11 12");
testDeleteSecondIfPossible ("[ 11 13 ]", "11 12 13");
testDeleteSecondIfPossible ("[ 11 13 14 ]", "11 12 13 14");
StdOut.println ("Finished tests");
}
/* ToString method to print */
public String toString () {
// Use DecimalFormat #.### rather than String.format 0.3f to leave off trailing zeroes
DecimalFormat format = new DecimalFormat ("#.###");
StringBuilder result = new StringBuilder ("[ ");
for (Node x = first; x != null; x = x.next) {
result.append (format.format (x.item));
result.append (" ");
}
result.append ("]");
return result.toString ();
}
/* Method to create lists */
public static CSC300Program4 of(String s) {
Node first = null;
String[] nums = s.split (" ");
for (int i = nums.length-1; i >= 0; i--) {
try {
double num = Double.parseDouble (nums[i]);
first = new Node (num, first);
} catch (NumberFormatException e) {
// ignore anything that is not a double
}
}
CSC300Program4 result = new CSC300Program4 ();
result.first = first;
return result;
}
// lots of copy and paste in these test!
private static void testSizeIterative (int expected, String sList) {
CSC300Program4 list = CSC300Program4.of (sList);
String sStart = list.toString ();
int actual = list.sizeIterative();
boolean status = true;
if (expected != actual) {
StdOut.format ("Failed %s.sizeIterative(): Expecting [%d] Actual [%d] ", sStart, expected, actual);
status = false;
}
String sEnd = list.toString ();
if (! sStart.equals (sEnd)) {
StdOut.format ("Failed %s.sizeIterative(): List changed to %s ", sStart, sEnd);
status = false;
}
if ( status && showMeSuccess)
StdOut.format ("Success sizeIterative(): Result: %d input: %s ", actual, sStart);
}
private static void testSizeRecursive (int expected, String sList) {
CSC300Program4 list = CSC300Program4.of (sList);
String sStart = list.toString ();
int actual = list.sizeRecursive();
boolean status = true;
if (expected != actual) {
StdOut.format ("Failed %s.sizeRecursive(): Expecting [%d] Actual [%d] ", sStart, expected, actual);
status = false;
}
String sEnd = list.toString ();
if (! sStart.equals (sEnd)) {
StdOut.format ("Failed %s.sizeRecursive(): List changed to %s ", sStart, sEnd);
status = false;
}
if ( status && showMeSuccess)
StdOut.format ("Success sizeRecursive(): Result: %d input: %s ", actual, sStart);
}
private static void testPositionOfFirstNumOccurrence (int expected, double num, String sList) {
CSC300Program4 list = CSC300Program4.of (sList);
String sStart = list.toString ();
int actual = list.positionOfFirstNumOccurrence(num);
boolean status = true;
if (expected != actual) {
StdOut.format ("Failed %s.positionOfFirstNumOccurrence(): Expecting [%d] Actual [%d] ", sStart, expected, actual);
status = false;
}
String sEnd = list.toString ();
if (! sStart.equals (sEnd)) {
StdOut.format ("Failed %s.positionOfFirstNumOccurrence(): List changed to %s ", sStart, sEnd);
status = false;
}
if ( status && showMeSuccess)
StdOut.format ("Success positionOfFirstNumOccurrence(): Result: %d position of first %.0f in %s ", actual, num , sStart);
}
private static void testSecondToLastValue (double expected, String sList) {
CSC300Program4 list = CSC300Program4.of (sList);
String sStart = list.toString ();
double actual = list.secondToLastValue();
boolean status = true;
if (expected != actual) {
StdOut.format ("Failed %s.secondToLastValue(): Expecting [%f] Actual [%f] ", sStart, expected, actual);
status = false;
}
String sEnd = list.toString ();
if (! sStart.equals (sEnd)) {
StdOut.format ("Failed %s.secondToLastValue(): List changed to %s ", sStart, sEnd);
status = false;
}
if ( status && showMeSuccess)
StdOut.format ("Success secondToLastValue(): Result: %.0f second to last value in %s ", actual, sStart);
}
private static void testDeleteSecondIfPossible (String expected, String sList) {
CSC300Program4 list = CSC300Program4.of (sList);
CSC300Program4 elist = CSC300Program4.of (expected);
list.deleteSecondIfPossible();
String actual = list.toString ();
expected = elist.toString();
boolean status = true;
if (! expected.equals(actual) ) {
StdOut.format ("Failed %s.deleteSecondIfPossible(): Expecting [%s] Actual [%s] ", sList, expected, actual);
status = false;
}
if ( status && showMeSuccess)
StdOut.format ("Success deleteSecondIfPossible(): Before: %s after %s ", expected, actual);
}
}
Explanation / Answer
Please find my implementation.
package year_2017.october.thirdweek;
import java.text.DecimalFormat;
public class CSC300Program4 {
// this class maintains a linked structure via the instance variable first
/*
* CSC300Program4 version 1.1
* fixed format specifier in function:
* testPositionOfFirstOccurence
*
*
* Does your program have compile errors? Yes / No
* Which TODOs have been completed correctly? Delete the lines below for TODOs that are NOT correct
* TODO 1
* TODO 2
* TODO 3
* TODO 4
* TODO 5
*
* Complete the methods below.
* None of the methods should modify the list, unless that is the purpose of the method.
*
* You may not add any fields to the node or list classes.
* You may not add any methods to the node class.
*
* You MAY add private methods to the CSC300Program4 class (helper functions for the recursion).
*/
static boolean showMeSuccess = false; // set to true to also see Success notifications for tests
// set to false to only see Failure notifications for tests
static class Node {
public Node (double item, Node next) { this.item = item; this.next = next; }
public double item;
public Node next;
}
Node first;
// a function to compute the size of the list, using a loop
// an empty list has size 0
public int sizeIterative () {
if(first == null)
return 0;
Node temp = first;
int count = 0;
while(temp != null) {
count++;
temp = temp.next;
}
return count;
}
// a function to compute the size of the list using recursion
// empty list has size 0
// You will want to create a helper function to do the recursion
public int sizeRecursive () {
return sizeRecursive(first);
}
private int sizeRecursive(Node head) {
if(head == null)
return 0;
return 1 + sizeRecursive(head.next);
}
// a function to compute the position of the first occurrence of NUM in the list,
// where NUM is passed as a parameter
// and positions are counted as an offset from the beginning.
//
// if NUM is 5.0 and 5.0 is the FIRST element, the position is 0
// if NUM is 5.0 and it does not appear, return -1
//
// you can write this iteratively or recursively, but you should only have one loop or recursive helper
// I would expect
// [0,1,2,5,5,5,5,5,8,9].positionOfFirstNumFromBeginning(5) == 3
// [0,1,3,4,5,5,2,5,8,9].positionOfFirstNumFromBeginning(2) == 6
public int positionOfFirstNumOccurrence (double num) {
Node temp = first;
int index = -1;
while(temp != null) {
index++;
if(temp.item == num)
return index;
temp = temp.next;
}
return -1;
}
// return the second-to-last value in the list,
// Precondition: the list has at least 2 values
// you can write this iteratively or recursively, but you should only have one loop or recursive helper
// you may not call any other method (e.g. size )
//
// [0,1,2,5,5,5,5,5,8,9].secondToLastValue() == 8
// [0,1].secondToLastValue() == 0
public double secondToLastValue ( ) {
Node curr = first.next;
Node prev = first;
while(curr.next != null) {
prev = curr;
curr = curr.next;
}
return prev.item;
}
// a function to delete the second node if it exists, if not, the list is unchanged
// [0,1,2,8,9].deleteSecondIfPossible() --> [0,2,8,9]
// [0,9].deleteSecondIfPossible() --> [0]
// [].deleteSecondIfPossible() --> []
public void deleteSecondIfPossible () {
if(first == null || first.next == null)
return;
first.next = first.next.next;
}
// for debugging purposes, you may comment/uncomment the two calls in main below
// you should restore the calls as below when you submit your solution
public static void main (String args[]) {
//mainDebug ();
mainRunTests ();
}
private static void mainDebug () {
// Use this for debugging!
// Add the names of helper functions if you use them.
Trace.drawStepsOfMethod ("sizeIterative");
Trace.drawStepsOfMethod ("sizeRecursive");
Trace.drawStepsOfMethod ("positionOfFirstNumOccurrence");
Trace.drawStepsOfMethod ("secondToLastValue");
Trace.drawStepsOfMethod ("deleteSecondIfPossible");
Trace.run ();
// To Use: Put the test here you want to debug:
testSizeIterative (4, "11 -21.2 31 41");
}
private static void mainRunTests () {
testSizeIterative (0, "");
testSizeIterative (1, "11");
testSizeIterative (2, "11 21");
testSizeIterative (4, "11 -21.2 31 41");
testSizeRecursive (0, "");
testSizeRecursive (1, "11");
testSizeRecursive (2, "11 21");
testSizeRecursive (4, "11 -21.2 31 41");
testPositionOfFirstNumOccurrence (-1, 99, "");
testPositionOfFirstNumOccurrence (-1, 99, "11");
testPositionOfFirstNumOccurrence (-1, 99, "11 21 31 41");
testPositionOfFirstNumOccurrence (0, 11, "11 21 31 41");
testPositionOfFirstNumOccurrence (3, 11, "5 21 31 11");
testPositionOfFirstNumOccurrence (0, 11, "11 11 11 11 11");
testPositionOfFirstNumOccurrence (2, 31, "11 21 31 31 41");
testSecondToLastValue (31, "11 21 31 41");
testSecondToLastValue (21, "11 21 31");
testSecondToLastValue (11, "11 21");
testDeleteSecondIfPossible ("[ ]", "");
testDeleteSecondIfPossible ("[ 11 ]", "11");
testDeleteSecondIfPossible ("[ 11 ]", "11 12");
testDeleteSecondIfPossible ("[ 11 13 ]", "11 12 13");
testDeleteSecondIfPossible ("[ 11 13 14 ]", "11 12 13 14");
System.out.println ("Finished tests");
}
/* ToString method to print */
public String toString () {
// Use DecimalFormat #.### rather than String.format 0.3f to leave off trailing zeroes
DecimalFormat format = new DecimalFormat ("#.###");
StringBuilder result = new StringBuilder ("[ ");
for (Node x = first; x != null; x = x.next) {
result.append (format.format (x.item));
result.append (" ");
}
result.append ("]");
return result.toString ();
}
/* Method to create lists */
public static CSC300Program4 of(String s) {
Node first = null;
String[] nums = s.split (" ");
for (int i = nums.length-1; i >= 0; i--) {
try {
double num = Double.parseDouble (nums[i]);
first = new Node (num, first);
} catch (NumberFormatException e) {
// ignore anything that is not a double
}
}
CSC300Program4 result = new CSC300Program4 ();
result.first = first;
return result;
}
// lots of copy and paste in these test!
private static void testSizeIterative (int expected, String sList) {
CSC300Program4 list = CSC300Program4.of (sList);
String sStart = list.toString ();
int actual = list.sizeIterative();
boolean status = true;
if (expected != actual) {
System.out.format ("Failed %s.sizeIterative(): Expecting [%d] Actual [%d] ", sStart, expected, actual);
status = false;
}
String sEnd = list.toString ();
if (! sStart.equals (sEnd)) {
System.out.format ("Failed %s.sizeIterative(): List changed to %s ", sStart, sEnd);
status = false;
}
if ( status && showMeSuccess)
System.out.format ("Success sizeIterative(): Result: %d input: %s ", actual, sStart);
}
private static void testSizeRecursive (int expected, String sList) {
CSC300Program4 list = CSC300Program4.of (sList);
String sStart = list.toString ();
int actual = list.sizeRecursive();
boolean status = true;
if (expected != actual) {
System.out.format ("Failed %s.sizeRecursive(): Expecting [%d] Actual [%d] ", sStart, expected, actual);
status = false;
}
String sEnd = list.toString ();
if (! sStart.equals (sEnd)) {
System.out.format ("Failed %s.sizeRecursive(): List changed to %s ", sStart, sEnd);
status = false;
}
if ( status && showMeSuccess)
System.out.format ("Success sizeRecursive(): Result: %d input: %s ", actual, sStart);
}
private static void testPositionOfFirstNumOccurrence (int expected, double num, String sList) {
CSC300Program4 list = CSC300Program4.of (sList);
String sStart = list.toString ();
int actual = list.positionOfFirstNumOccurrence(num);
boolean status = true;
if (expected != actual) {
System.out.format ("Failed %s.positionOfFirstNumOccurrence(): Expecting [%d] Actual [%d] ", sStart, expected, actual);
status = false;
}
String sEnd = list.toString ();
if (! sStart.equals (sEnd)) {
System.out.format ("Failed %s.positionOfFirstNumOccurrence(): List changed to %s ", sStart, sEnd);
status = false;
}
if ( status && showMeSuccess)
System.out.format ("Success positionOfFirstNumOccurrence(): Result: %d position of first %.0f in %s ", actual, num , sStart);
}
private static void testSecondToLastValue (double expected, String sList) {
CSC300Program4 list = CSC300Program4.of (sList);
String sStart = list.toString ();
double actual = list.secondToLastValue();
boolean status = true;
if (expected != actual) {
System.out.format ("Failed %s.secondToLastValue(): Expecting [%f] Actual [%f] ", sStart, expected, actual);
status = false;
}
String sEnd = list.toString ();
if (! sStart.equals (sEnd)) {
System.out.format ("Failed %s.secondToLastValue(): List changed to %s ", sStart, sEnd);
status = false;
}
if ( status && showMeSuccess)
System.out.format ("Success secondToLastValue(): Result: %.0f second to last value in %s ", actual, sStart);
}
private static void testDeleteSecondIfPossible (String expected, String sList) {
CSC300Program4 list = CSC300Program4.of (sList);
CSC300Program4 elist = CSC300Program4.of (expected);
list.deleteSecondIfPossible();
String actual = list.toString ();
expected = elist.toString();
boolean status = true;
if (! expected.equals(actual) ) {
System.out.format ("Failed %s.deleteSecondIfPossible(): Expecting [%s] Actual [%s] ", sList, expected, actual);
status = false;
}
if ( status && showMeSuccess)
System.out.format ("Success deleteSecondIfPossible(): Before: %s after %s ", expected, actual);
}
}