Develop Reference

I have some problems with ArrayList (quiz of head first java)

I've just started learning java since last week. I'm using book called 'head first java' and i'm struggling with solving problems about ArrayList. Error says "The method setLocationCells(ArrayList) in the type DotCom is not applicable for the
arguments (int[])" and I haven't found the solution :( help me..!
enter image description here

This looks like a Locate & Conquer type game similar to the game named Battleship with the exception that this game is a single player game played with a single hidden ship in a single horizontal row of columnar characters. Rather simplistic but kind of fun to play I suppose. The hard part is to locate the hidden ship but once you've located it, conquering (sinking) it becomes relatively easy. I'm sure this isn't the games' intent since it is after all named "The Dot Com Game" but the analogy could be possibly helpful.
There are several issues with your code but there are two major ones that just can not be there for the game to work:
Issue #1: The call to the DotCom.setLocationCells() method:
The initial problem is located within the DotComGame class on code line 13 (as the Exception indicates) where the call is made to the DotCom.setLocationCells() method. As already mentioned in comments the wrong parameter type is passed to this method. You can not pass an int[] Array to the setLocationCell() method when this method contains a parameter signature that stipulates it requires an ArrayList object. The best solution in my opinion would be to satisfy the setLocationCells() method parameter requirement...supply an ArrayList to this method.
The reason I say this is because all methods within the DotCom class work with an established ArrayList and one of the tasks of one of these methods (the checkYourself() method) actually removes elements from the ArrayList which is easy to do from a collection but very cumbersome to do the same from an Array.
To fix this problem you will need to change the data type for the locations variable located within the DotComGame class. Instead of using:
int[] locations = {randomNum, randomNum + 1, randomNum + 2};
you should have:
ArrayList<Integer> locations = new ArrayList<>(
Arrays.asList(random, randomNum + 1, randomNum + 2));
or you could do it this way:
ArrayList<Integer> locations = new ArrayList<>();
locations.add(randomNum);
locations.add(randomNum + 1);
locations.add(randomNum + 2);
There are other ways but these will do for now. Now, when the call to the setLocationCells() method is made you ahouldn't get an exception this issue should now be resolved.
Issue #2: The call to the DotCom.checkYourself() method:
Again, this particular issue is located within the DotComGame class on code line 18 where the call is made to the DotCom.checkYourself() method. Yet another parameter data type mismatch. You are trying to pass a variable of type String (named guess) to this method whereas its signature stipulates that it requires an integer (int) value. That again is a no go.
To fix this problem you will need to convert the string numerical value held by the guess variable to an Integer (int) value. So instead of having this:
while(isAlive) {
String guess = helper.getUserInput("Enter a Number: ");
String result = theDotCom.checkYourself(guess);
// ... The rest of your while loop code ...
}
you should have something like:
while(isAlive) {
String guess = helper.getUserInput("Enter a Number: ");
/* Validate. Ensure guess holds a string representation
of a Integer numerical value. */
if (!guess.matches("\\d+")) {
System.err.println("Invalid Value (" + guess
+ ") Supplied! Try again...");
continue;
}
int guessNum = Integer.parseInt(guess);
String result = theDotCom.checkYourself(guessNum);
numOfGuesses++;
if (result.equals("kill")) {
isAlive = false;
System.out.println(numOfGuesses + " guesses!");
}
else if (result.equals("hit")) {
// Do Something If You Like
System.out.println("HIT!");
}
else {
System.out.println("Missed!");
}
}
Below is a game named Simple Battleship which I based off of your code images (please don't use images for code anymore - I hate using online OCR's ;)
BattleshipGame.java - The application start class:
import java.awt.Toolkit;
public class BattleshipGame {
public static int gameLineLength = 10;
public static void main(String[] args) {
GameHelper helper = new GameHelper();
Battleship theDotCom = new Battleship();
int score = 0; // For keeping an overall score
// Display About the game...
System.out.println("Simple Battleship Game");
System.out.println("======================");
System.out.println("In this game you will be displayed a line of dashes.");
System.out.println("Each dash has the potential to hide a section of a");
System.out.println("hidden Battleship. The size of this ship is randomly");
System.out.println("chosen by the game engine and can be from 1 to 5 sections");
System.out.println("(characters) in length. The score for each battle is based");
System.out.println("on the length of the game line that will be displayed to");
System.out.println("you (default is a minimum of 10 charaters). You now have");
System.out.println("the option to supply the game line length you want to play");
System.out.println("with. If you want to use the default then just hit ENTER:");
System.out.println();
// Get the desire game line length
String length = helper.getUserInput("Desired Game Line Length: --> ", "Integer", true, 10, 10000);
if (!length.isEmpty()) {
gameLineLength = Integer.parseInt(length);
}
System.out.println();
// Loop to allow for continuous play...
boolean alwaysReplay = true;
while (alwaysReplay) {
int numOfGuesses = 0;
/* Create a random ship size to hide within the line.
It could be a size from 1 to 5 characters in length. */
int shipSize = new java.util.Random().nextInt((5 - 1) + 1) + 1;
int randomNum = (int) (Math.random() * (gameLineLength - (shipSize - 1)));
int[] locations = new int[shipSize];
for (int i = 0; i < locations.length; i++) {
locations[i] = randomNum + i;
}
System.out.println("Destroy the " + shipSize + " character ship hidden in the");
System.out.println("displayed line below:");
System.out.println();
String gameLine = String.join("", java.util.Collections.nCopies(gameLineLength, "-"));
theDotCom.setLocationCells(locations);
// Play current round...
boolean isAlive = true;
while (isAlive == true) {
System.out.println(gameLine);
String guess = helper.getUserInput("Enter a number from 1 to " + gameLineLength
+ " (0 to quit): --> ", "Integer", 1, gameLineLength);
int idx = Integer.parseInt(guess);
if (idx == 0) {
System.out.println("Quiting with an overall score of: " + score + " ... Bye-Bye");
alwaysReplay = false;
break;
}
idx = idx - 1;
String result = theDotCom.checkYourself(idx);
numOfGuesses++;
System.out.println(result);
if (result.equalsIgnoreCase("kill")) {
Toolkit.getDefaultToolkit().beep();
isAlive = false;
/* Tally the score dependent upon the gameLineLength... */
if (gameLineLength <= 10) { score += 5; }
else if (gameLineLength > 10 && gameLineLength <= 20) { score += 10; }
else if (gameLineLength > 20 && gameLineLength <= 30) { score += 15; }
else if (gameLineLength > 30 && gameLineLength <= 40) { score += 20; }
else { score += 25; }
gameLine = gameLine.substring(0, idx) + "x" + gameLine.substring(idx + 1);
System.out.println(gameLine);
System.out.println(numOfGuesses + " guesses were made to sink the hidden ship.");
System.out.println("Your overall score is: " + (score < 0 ? 0 : score));
}
else if (result.equalsIgnoreCase("hit")) {
gameLine = gameLine.substring(0, idx) + "x" + gameLine.substring(idx + 1);
}
if (result.equalsIgnoreCase("miss")) {
score -= 1;
}
System.out.println();
}
// Play Again? [but only if 'alwaysReplay' holds true]
if (alwaysReplay) {
String res = helper.getAnything("<< Press ENTER to play again >>\n"
+ "<< or enter 'q' to quit >>");
if (res.equalsIgnoreCase("q")) {
System.out.println("Quiting with an overall score of: " + score + " ... Bye-Bye");
break;
}
System.out.println();
}
}
}
}
GameHelper.java - The GameHelper class:
import java.util.Scanner;
public class GameHelper {
private final Scanner in = new Scanner(System.in);
public String getUserInput(String prompt, String responseType, int... minMAX) {
int min = 0, max = 0;
if (minMAX.length == 2) {
min = minMAX[0];
max = minMAX[1];
}
if (minMAX.length > 0 && min < 1 || max < 1) {
throw new IllegalArgumentException("\n\ngetUserInput() Method Error! "
+ "The optional parameters 'min' and or 'max' can not be 0!\n\n");
}
String response = "";
while (response.isEmpty()) {
if (prompt.trim().endsWith("-->")) {
System.out.print(prompt);
}
else {
System.out.println(prompt);
}
response = in.nextLine().trim();
if (responseType.matches("(?i)\\b(int|integer|float|double)\\b")) {
if (!response.matches("-?\\d+(\\.\\d+)?") ||
(responseType.toLowerCase().startsWith("int") && response.contains("."))) {
System.err.println("Invalid Entry (" + response + ")! Try again...");
response = "";
continue;
}
}
// Check entry range value if the entry is to be an Integer
if (responseType.toLowerCase().startsWith("int")) {
int i = Integer.parseInt(response);
if (i != 0 && (i < min || i > max)) {
System.err.println("Invalid Entry (" + response + ")! Try again...");
response = "";
}
}
}
return response;
}
public String getUserInput(String prompt, String responseType, boolean allowNothing, int... minMAX) {
int min = 0, max = 0;
if (minMAX.length == 2) {
min = minMAX[0];
max = minMAX[1];
}
if (minMAX.length > 0 && min < 1 || max < 1) {
throw new IllegalArgumentException("\n\ngetUserInput() Method Error! "
+ "The optional parameters 'min' and or 'max' can not be 0!\n\n");
}
String response = "";
while (response.isEmpty()) {
if (prompt.trim().endsWith("-->")) {
System.out.print(prompt);
}
else {
System.out.println(prompt);
}
response = in.nextLine().trim();
if (response.isEmpty() && allowNothing) {
return "";
}
if (responseType.matches("(?i)\\b(int|integer|float|double)\\b")) {
if (!response.matches("-?\\d+(\\.\\d+)?") ||
(responseType.toLowerCase().startsWith("int") && response.contains("."))) {
System.err.println("Invalid Entry (" + response + ")! Try again...");
response = "";
continue;
}
}
// Check entry range value if the entry is to be an Integer
if (responseType.toLowerCase().startsWith("int")) {
int i = Integer.parseInt(response);
if (i != 0 && (i < min || i > max)) {
System.err.println("Invalid Entry (" + response + ")! Try again...");
response = "";
}
}
}
return response;
}
public String getAnything(String prompt) {
if (prompt.trim().endsWith("-->")) {
System.out.print(prompt);
}
else {
System.out.println(prompt);
}
return in.nextLine().trim();
}
}
Battleship.java - The Battleship class:
import java.util.ArrayList;
public class Battleship {
private ArrayList<Integer> locationCells;
public void setLocationCells(java.util.ArrayList<Integer> loc) {
locationCells = loc;
}
// Overload Method (Java8+)
public void setLocationCells(int[] loc) {
locationCells = java.util.stream.IntStream.of(loc)
.boxed()
.collect(java.util.stream.Collectors
.toCollection(java.util.ArrayList::new));
}
/*
// Overload Method (Before Java8)
public void setLocationCells(int[] loc) {
// Clear the ArrayList in case it was previously loaded.
locationCells.clear();
// Fill the ArrayList with integer elements from the loc int[] Array
for (int i = 0; i < loc.length; i++) {
locationCells.add(loc[i]);
}
}
*/
/**
* Completely removes one supplied Integer value from all elements
* within the supplied Integer Array if it exist.<br><br>
*
* <b>Example Usage:</b><pre>
*
* {#code int[] a = {103, 104, 100, 10023, 10, 140, 2065};
* a = removeFromArray(a, 104);
* System.out.println(Arrays.toString(a);
*
* // Output will be: [103, 100, 10023, 10, 140, 2065]}</pre>
*
* #param srcArray (Integer Array) The Integer Array to remove elemental
* Integers from.<br>
*
* #param intToDelete (int) The Integer to remove from elements within the
* supplied Integer Array.<br>
*
* #return A Integer Array with the desired elemental Integers removed.
*/
public static int[] removeFromArray(int[] srcArray, int intToDelete) {
int[] arr = {};
int cnt = 0;
boolean deleteIt = false;
for (int i = 0; i < srcArray.length; i++) {
if (srcArray[i] != intToDelete) {
arr[cnt] = srcArray[i];
cnt++;
}
}
return arr;
}
public String checkYourself(int userInput) {
String result = "MISS";
int index = locationCells.indexOf(userInput);
if (index >= 0) {
locationCells.remove(index);
if (locationCells.isEmpty()) {
result = "KILL";
}
else {
result = "HIT";
}
}
return result;
}
}

Why odd characters appear when printing large ArrayLists

I am following a tutorial which partially deals with printing the elements of ArrayLists. The program runs exactly as I'd expect when dealing with small lists. However the string formatting ( I believe ) causes some strange results when larger numbers are input.
My code is as follows:
public class Theatre {
private final String theatreName;
public List<Seat> seats = new ArrayList<>();
public Theatre(String theatreName, int numRows, int seatsPerRow) {
this.theatreName = theatreName;
int lastRow = 'A' + (numRows -1);
for (char row = 'A'; row <= lastRow; row++) {
for(int seatNum = 1; seatNum <= seatsPerRow; seatNum++) {
Seat seat = new Seat(row + String.format("%02d", seatNum));
seats.add(seat);
}
}
}
public String getTheatreName() {
return theatreName;
}
public boolean reserveSeat(String seatNumber) {
int low = 0;
int high = seats.size()-1;
while(low <= high) {
System.out.print(".");
int mid = (low + high) /2;
Seat midVal = seats.get(mid);
int cmp = midVal.getSeatNumber().compareTo(seatNumber);
if(cmp <0) {
low = mid + 1;
} else if(cmp > 0) {
high = mid -1;
} else {
return seats.get(mid).reserve();
}
}
System.out.println("There is no seat " + seatNumber);
return false;
}
// for testing
public void getSeats() {
for(Seat seat : seats) {
System.out.println(seat.getSeatNumber());
}
}
public class Seat implements Comparable<Seat > {
private final String seatNumber;
private boolean reserved = false;
public Seat(String seatNumber) {
this.seatNumber = seatNumber;
}
public boolean reserve() {
if(!this.reserved) {
this.reserved = true;
System.out.println("Seat " + seatNumber + " reserved");
return true;
} else {
return false;
}
}
public boolean cancel() {
if(this.reserved) {
this.reserved = false;
System.out.println("Reservation of seat " + seatNumber + " cancelled");
return true;
} else {
return false;
}
}
public String getSeatNumber() {
return seatNumber;
}
#Override
public int compareTo(Seat seat) {
// returns integer greater than 0 if greater than, less than if less than, 0 if equal
return this.seatNumber.compareTo(seat.getSeatNumber());
}
}
With a Main method class:
public static void main(String[] args) {
Theatre theatre = new Theatre("Olympian", 800, 12);
List<Theatre.Seat> seatCopy = new ArrayList<>(theatre.seats); // shallow copy, contains references to all
// elements of both lists, original and copy
printList(seatCopy);
seatCopy.get(1).reserve();
if (theatre.reserveSeat("A02")) {
System.out.println("Please pay for A02");
} else {
System.out.println("seat already reserved");
}
// see that they are clearly two separate array lists
Collections.reverse(seatCopy);
System.out.println("Printing seat copy");
printList(seatCopy);
System.out.println("Printing theatre.seats");
printList(theatre.seats);
System.out.println("Shuffling seatCopy");
Collections.shuffle(seatCopy);
printList(seatCopy);
}
public static void printList(List<Theatre.Seat> list) {
for (Theatre.Seat seat : list) {
System.out.print(" " + seat.getSeatNumber());
}
System.out.println();
System.out.println("===============================");
}
}
The output (I only quote enough to see ) is:
12 ͠11 ͠10 ͠09 ͠08 ͠07 ͠06 ͠05 ͠04 ͠03 ͠02 ͠01 ͟12 ͟
===============================
Printing theatre.seats
A01 A02 A03 A04 A05 A06 A07 A08 A09 A10
===============================
===============================
Shuffling seatCopy
V07 Ý11 11 ű05 Ú02 ̄06 ̓01 ŕ12 ȣ03 Ǔ05 S07
I am aware that I run out of alphabetical characters and that the formatting in this line:
Seat seat = new Seat(row + String.format("%02d", seatNum));
is intended only to deal with seats of the format "X##".
What I want to understand is specificallty why the odd characters appear ( the "~" and "'", etc. ). Obviously, the formatting is inappropriate. But why does it produce specifically this output?
Thank you for your help,
Marc

You said it yourself. You're running out of alphabetical characters. In fact, you're running out of ASCII characters altogether. From this line:
for (char row = 'A'; row <= lastRow; row++)
What you are doing is starting the row letters from 'A' and continuing across the Unicode character set. So, with more than 26 rows, you start getting symbols like ~, and with enough rows, you leave ASCII altogether and start getting weird row letters like Ý.
If you don't want this to happen, you'll need to ditch the for loop and come up with an entirely different (and more complex) way of assigning row labels.

Convert String representation to minimal Number Object

Having a String representation of a number(no decimals), what's the best way to convert it to either one of java.lang.Integer or java.lang.Long or java.math.BigInteger? The only condition is that the converted type should be of minimal datatype required to hold the number.
I've this current implementation that works fine, but I would like to know if there's a better code without exception handling.
package com.stackoverflow.programmer;
import java.math.BigInteger;
public class Test {
public static void main(String[] args) {
String number = "-12121111111111111";
Number numberObject = null;
try {
numberObject = Integer.valueOf(number);
} catch (NumberFormatException nfe) {
System.out.println("Number will not fit into Integer type. Trying Long...");
try {
numberObject = Long.valueOf(number);
} catch (NumberFormatException nfeb) {
System.out.println("Number will not fit into Long type. Trying BigInteger...");
numberObject = new BigInteger(number);
}
}
System.out.println(numberObject.getClass() + " : "
+ numberObject.toString());
}
}

From what you said, here is what I would have done:
import java.math.BigInteger;
import java.util.Arrays;
import java.util.List;
public class TestSO09_39463168_StringToMinimalNumber {
public static void main(String[] args) {
List<String> strNumbers = Arrays.asList("0", //int
"123", //int
"-456", //int
"2147483700", // Long
"-2147483700", // Long
"9223372036854775900", //BigInt
"-9223372036854775900" //BigInt
);
for(String strNumber : strNumbers){
Number number = stringToMinimalNumber(strNumber);
System.out.println("The string '"+strNumber+"' is a "+number.getClass());
}
}
public static Number stringToMinimalNumber(String s){
BigInteger tempNumber = new BigInteger(s);
if(tempNumber.compareTo(BigInteger.valueOf(Long.MAX_VALUE)) > 0 || tempNumber.compareTo(BigInteger.valueOf(Long.MIN_VALUE)) < 0){
return tempNumber;
} else if(tempNumber.compareTo(BigInteger.valueOf(Integer.MAX_VALUE)) > 0 || tempNumber.compareTo(BigInteger.valueOf(Integer.MIN_VALUE)) < 0){
return tempNumber.longValue(); //Autobox to Long
} else {
return tempNumber.intValue(); //Autobox to Integer
}
}
}
You must use a temporary BigInteger, or else you'll end up with lazarov's solution, which is correct, but you can't really do something like that for reason mentionned in the comments.
Anyway, every BigInteger (the ones that are not returned) will be garbage collected. As for autoboxing, I don't think it's that of a bad thing. You could also make "BigInteger.valueOf(Long.MAX_VALUE))" as a constant. Maybe the compiler or the JVM will do this on its own.
I'm not really sure of how efficient it is, and using only BigInteger might be a good idea (as Spotted did), because I serioulsy doubt it would really improve the rest of your code to use the right size, and it might even be error prone if you try to use these Numbers with each other ... But again, it all depend on what you need. (and yes, using Exception as flow control is a really bad idea, but you can add a try catch on the BigInteger tempNumber = new BigInteger(s); to throw your own exception if s is not a number at all)
For recreational purpose, I have made the solution without using a BigInteger, and only with String parsing (this is still not what I recommand to do, but it was fun :)
public static final String INT_MAX_VALUE = "2147483647";
public static final String LONG_MAX_VALUE = "9223372036854775807";
public static Number stringToMinimalNumberWithoutBigInteger(String numberStr){
//Removing the minus sign to test the value
String s = (numberStr.startsWith("-") ? numberStr.substring(1,numberStr.length()) : numberStr);
if(compareStringNumber(s, LONG_MAX_VALUE) > 0){
return new BigInteger(numberStr);
} else if(compareStringNumber(s, INT_MAX_VALUE) > 0){
return new Long(numberStr);
} else {
return new Integer(numberStr);
}
}
//return postive if a > b, negative if a < b, 0 if equals;
private static int compareStringNumber(String a, String b){
if(a.length() != b.length()){
return a.length() - b.length();
}
for(int i = 0; i < a.length(); i++){
if( a.codePointAt(i) != b.codePointAt(i) ){ //Or charAt()
return a.codePointAt(i) - b.codePointAt(i);
}
}
return 0;
}

Please don't use exceptions for handling flow control, this is a serious anti-pattern (also here).
As you mentionned in the comments, the real thing you've been asked is to convert a List<String> into a List<Number>.
Also, if I understand correctly, you know that:
You should encounter only numbers without decimals
The biggest value you can encounter is possibly unbound
Based on that, the following method will do the job in a more clever way:
private static List<Number> toNumbers(List<String> strings) {
return strings.stream()
.map(BigInteger::new)
.collect(Collectors.toList());
}
Eidt: if you're not very familiar with the stream concept, here's the equivalent code without streams:
private static List<Number> toNumbers(List<String> strings) {
List<Number> numbers = new ArrayList<>();
for (String s : strings) {
numbers.add(new BigInteger(s));
}
return numbers;
}

Well if you want to do it "by hand" try something like this:
We define the max values as strings :
String intMax = "2147483647";
String longMax = "9223372036854775807";
and our number:
String ourNumber = "1234567890"
Now our logic will be simple :
We will check lenghts of strings firstly
If our numbers length < int max length : IT IS INT
If our numbers length == int max length : Check is it INT or LONG
If our numbers length > int max length :
3.1 If our numbers length < long max length : IT IS LONG
3.2 If our numbers length == long max length : Check is it LONG or BIG INTEGER
3.3 If our numbers length > long max length : IT IS BIG INTEGER
The code should look something like this (I have not tried to compile it may have syntax or other errors) :
if(ourNumber.lenght() < intMax.length ){
System.out.println("It is an Integer");
} else if(ourNumber.lenght() == intMax.length){
// it can be int if the number is between 2000000000 and 2147483647
char[] ourNumberToCharArray = ourNumber.toCharArray();
char[] intMaxToCharArray = intMax.toCharArray();
int diff = 0;
for(int i = 0; i < ourNumberToCharArray.length; i++) {
diff = Character.getNumericValue(intMaxToCharArray[i]) - Character.getNumericValue(ourNumberToCharArray[i]);
if(diff > 0) {
System.out.println("It is a Long");
break;
} else if(diff < 0) {
System.out.println("It is an Integer");
break;
}
}
if(diff == 0){
System.out.println("It is an Integer");
}
} else {
if(ourNumber.lenght() < longMax.length()) {
System.out.println("It is a Long");
} else if(ourNumber.lenght() == longMax.length()){
char[] ourNumberToCharArray = ourNumber.toCharArray();
char[] longMaxToCharArray = longMax.toCharArray();
int diff = 0;
for(int i = 0; i < ourNumberToCharArray.length; i++) {
diff = Character.getNumericValue(longMaxToCharArray[i]) - Character.getNumericValue(ourNumberToCharArray[i]);
if(diff > 0) {
System.out.println("It is a BigInteger");
break;
} else if(diff < 0) {
System.out.println("It is a Long");
break;
}
}
if(diff == 0){
System.out.println("It is a Long");
}
} else {
System.out.println("It is a BigInteger");
}
}
Then logic that checks if the numbers match or not is the same in both cases you can but it in a function for example.

Loop is skipping statement (CASINO PROGRAM)

I'm trying to make a casino program for my school project. Everything seems to work just fine except that the statement of the do-while loop inside the main() method is always skipped at the first, third, fifth (odd) lines in the console.
THE PROGRAM:
import java.util.Scanner;
import java.text.*;
import java.util.*;
public class Casino
{
public static Scanner input;
static final String SEPARATOR = "\n";
public static void main (String[] args) throws Exception
{
int winnings;
while (getBet() != 0)
{
TripleString thePull = pull();
getPayMultiplier(thePull);
winnings = getPayMultiplier(thePull) * getBet();
display(thePull, winnings);
}
System.out.println("Thanks");
}
//gets bet, stores in static class variables
public static int getBet()
{
final double MAX_BET = 50;
String prompt, strUserResponse;
int intResponse;
input = new Scanner(System.in);
do
{
prompt = "How much would you like to bet ( Min $1 - Max $50 ) "
+ "or press '0' to quit?";
System.out.print(prompt);
strUserResponse = input.nextLine();
intResponse = Integer.parseInt(strUserResponse);
}
while( intResponse < 0 || intResponse > MAX_BET );
return intResponse;
}
public static String randString()
{
int bar = 38;
int cherries = 78;
int space = 85;
int seven = 100;
String randomString = "";
int randomNum = 1 + (int)(Math.random() * 100);
if (randomNum <= bar)
randomString = "BAR";
else if (randomNum <= cherries)
randomString = "cherries";
else if (randomNum <= space)
randomString = "space";
else if (randomNum <= seven)
randomString = "7";
return randomString;
}
public static TripleString pull()
{
TripleString pullString = new TripleString();
String str1 = randString();
pullString.setString1(str1);
String str2 = randString();
pullString.setString2(str2);
String str3 = randString();
pullString.setString3(str3);
return pullString;
}
public static int getPayMultiplier (TripleString thePull)
{
if (thePull.getString1() == "cherries" &&
thePull.getString2() != "cherries" )
return 5;
else if (thePull.getString1() == "cherries" &&
thePull.getString2() == "cherries" &&
thePull.getString3() != "cherries")
return 15;
else if (thePull.getString1() == "cherries" &&
thePull.getString2() == "cherries" &&
thePull.getString3() == "cherries")
return 30;
else if (thePull.getString1() == "BAR" &&
thePull.getString2() == "BAR" &&
thePull.getString3() == "BAR")
return 50;
else if (thePull.getString1() == "7" &&
thePull.getString2() == "7" &&
thePull.getString3() == "7")
return 100;
else
return 0;
}
public static void display (TripleString thePull, int winnings)
{
System.out.println(SEPARATOR + ">>>Brrrrrr! Your Pull Is . . .<<<"
+ SEPARATOR + thePull.toString());
if ( winnings == 0)
System.out.println("Sorry you lose. . . GOOD LUCK NEXT TIME!"
+ SEPARATOR);
else
System.out.println("Congaratulations, you win =" + " $" + winnings
+ " !" + SEPARATOR + "YEAY !!! :):):)" + SEPARATOR);
}
}
class TripleString
{
//member data
private String string1, string2, string3;
//static constants
public static final double MIN_LEN = 1;
public static final double MAX_LEN = 50;
public static final String DEFAULT_STRING = "undefined";
//default constructor
TripleString ()
{
string1 = DEFAULT_STRING;
string2 = DEFAULT_STRING;
string3 = DEFAULT_STRING;
}
//parameter-taking constructor
TripleString (String str1, String str2, String str3)
{
if (! setString1(str1))
str1 = DEFAULT_STRING;
if (! setString2(str2))
str2 = DEFAULT_STRING;
if (! setString3(str3))
str3 = DEFAULT_STRING;
}
//private static helper method
private boolean validString(String str)
{
if (str == null || str.length() < MIN_LEN || str.length() > MAX_LEN)
return false;
else
return true;
}
//accessor set methods
public boolean setString1 (String stringName1)
{
if ( !validString(stringName1) )
return false;
string1 = stringName1;
return true;
}
public boolean setString2 (String stringName2)
{
if ( !validString(stringName2) )
return false;
string2 = stringName2;
return true;
}
public boolean setString3 (String stringName3)
{
if ( !validString(stringName3) )
return false;
string3 = stringName3;
return true;
}
//accessor get methods
public String getString1 () { return string1; }
public String getString2 () { return string2; }
public String getString3 () { return string3; }
public String toString ()
{
String reStr;
reStr = string1 + " "+ string2 + " " + string3;
return reStr;
}
}
Here is the example of my run:
How much would you like to bet ( Min $1 - Max $50 ) or press '0' to quit?1
How much would you like to bet ( Min $1 - Max $50 ) or press '0' to quit?6
//Brrrrr below supposed to have ">>>" "<<<" but I remove it manually in this example since it creates blockquotes
Brrrrrr! Your Pull Is . . .
cherries cherries BAR
Congaratulations, you win = $90 !
YEAY !!! :):):)
How much would you like to bet ( Min $1 - Max $50 ) or press '0' to quit?7
How much would you like to bet ( Min $1 - Max $50 ) or press '0' to quit?7
Brrrrrr! Your Pull Is . . .
7 BAR cherries
Sorry you lose. . . GOOD LUCK NEXT TIME!
I want to make it looks more like
How much would you like to bet ( Min $1 - Max $50 ) or press '0' to quit?1
Brrrrrr! Your Pull Is . . .<<<
BAR BAR BAR
Congaratulations, you win = $50 !
YEAY !!! :):):)
How much would you like to bet ( Min $1 - Max $50 ) or press '0' to quit?2
Brrrrrr! Your Pull Is . . .<<<
BAR cherries BAR
Sorry you lose. . . GOOD LUCK NEXT TIME!
How much would you like to bet ( Min $1 - Max $50 ) or press '0' to quit?0
I think the problem has to be related with the loop in my getInput() method, but I'm really not sure why. I know I could've not make a loop in the getInput() method, but my instructor specifies that the method has to loop until the user put the valid #(1-50)
I've tried changing it to the standard while loop or modifying the code in many other way, but in new ways come new problems. For example, if I change my main method to
Alternate main()
public static void main (String[] args) throws Exception
{
int bet = getBet(), winnings;
do
{
TripleString thePull = pull();
getPayMultiplier(thePull);
winnings = getPayMultiplier(thePull) * bet;
display(thePull, winnings);
}
while (getBet() != 0);
System.out.println("Thanks");
}
If I use the above code for the main, my variable bet will stay the same for every loop since it has been initiated before that.
Edit: the alternate main() method
Edit2: Add more sample run

Your second main does not work, because you do not re-assign the bet variable.
Working simple alternate main()
public static void main (String[] args) throws Exception
{
int bet = getBet(), winnings;
do
{
TripleString thePull = pull();
getPayMultiplier(thePull);
winnings = getPayMultiplier(thePull) * bet;
display(thePull, winnings);
bet = getBet();
}
while ( bet != 0);
System.out.println("Thanks");
}
Your first main does not work because you call getBet() twice
Working main
public static void main (String[] args) throws Exception
{
int winnings;
int bet;
while ((bet = getBet()) != 0)
{
TripleString thePull = pull();
getPayMultiplier(thePull);
winnings = getPayMultiplier(thePull) * bet;
display(thePull, winnings);
}
System.out.println("Thanks");
}

If you want your bet variable to not remain the same, you can change the while loop to simply:
while(true){
//get the bet here
if(bet == 0){
break;
}
//Do the rest of your stuff here.
}
This will change the bet every iteration but still stop running if it is zero.

Validate routing number

How to validate bank routing number in java ?
can any one help me out.
for example
void boolean validate(String str){
// some code
return true; //if valid otherwise return false
}

Please find who needs a routing number validator.
routing-number.validator.ts
import { AbstractControl, ValidationErrors } from '#angular/forms';
export const routingNumberValidator = (): ((AbstractControl) => ValidationErrors | null) => {
return (control: AbstractControl): ValidationErrors | null => {
const targetValue = control.value;
if (!targetValue) {
return null;
}
const digits = targetValue.split('').map(d => parseInt(d, 10));
const checksum = 3 * (digits[0] + digits[3] + digits[6]) + 7 * (digits[1] + digits[4] + digits[7]) + (digits[2] + digits[5] + digits[8]);
return (checksum % 10 === 0) ? null : { routingnumber: true };
};
};
In your yourComponent.component.ts:
this.yourForm = this.fb.group({
routingNumber: [null, Validators.compose([
Validators.required,
routingNumberValidator()
])]
});
And in your yourComponent.component.html:
<nz-form-control [nzErrorTip]="routingNumberErrorTemplate">
<input
nz-input
formControlName="routingNumber"
id="routingNumber">
</nz-form-control>
<ng-template
#routingNumberErrorTemplate
let-control>
<span data-cy="routing-number-input-error">
<ng-container *ngIf="control.hasError('required')">The routing number is required</ng-container>
<ng-container *ngIf="control.hasError('routingnumber')">The routing number is invalid</ng-container>
</span>
</ng-template>

I got the solution. Bank Routing Number is validate by using this simple method.
public boolean validateRoutingNumber(String s) {
int checksum=0, len=0, sum=0, mod = 0;
len = s.length();
if(len != 9){
return false;
}else {
String newString = s.substring(s.length()-1);
checksum = Integer.parseInt(newString);
sum = (7*(Integer.parseInt(""+s.charAt(0))+Integer.parseInt(""+s.charAt(3))+ Integer.parseInt(""+s.charAt(6)))) +
(3*(Integer.parseInt(""+s.charAt(1))+Integer.parseInt(""+s.charAt(4))+ Integer.parseInt(""+s.charAt(7))))+
(9*(Integer.parseInt(""+s.charAt(2))+Integer.parseInt(""+s.charAt(5))));
mod = sum % 10;
if(mod == checksum)
return true;
else
return false;
}
}

Just for fun, I wrote a Angular js directive for doing this same thing:
angular.module('ldPortal.directives')
.directive('routingnumber', function(){
return {
// only use as an attribute
restrict: 'A',
require: 'ngModel',
link: function(scope, elem, attr, ctrl){
var regex = new RegExp('^[0-9]{9}$','');
var num_at = function(str, index){
try {
return parseInt(str.charAt(index))
}catch (execption){
console.write(execption);
}
};
var validate = function(value){
if(! (value)){
return false;
}
var strVal = value.toString();
if (!regex.test(strVal)){
return false;
}
var checksum = parseInt(strVal.substr(strVal.length-1));
var sum = 0;
sum += 7 * (num_at(strVal, 0)+num_at(strVal, 3)+num_at(strVal,6));
sum += 3 * (num_at(strVal, 1)+num_at(strVal, 4)+num_at(strVal, 7));
sum += 9 * (num_at(strVal, 2)+num_at(strVal, 5));
var mod = sum % 10;
return checksum == mod;
};
ctrl.$parsers.push(function(value){
var is_valid = validate(value);
ctrl.$setValidity('routingnumber', is_valid);
return is_valid ? value : undefined;
});
ctrl.$formatters.push(function(value){
var is_valid = validate(value);
ctrl.$setValidity('routingnumber', is_valid);
return value;
});
}
};
});

I created a simple Routing Validator, hope this works.
RoutingNumberValidator:
import static java.lang.Character.getNumericValue;
public static class RoutingNumberValidator {
public boolean isValid(String value) {
boolean isValid = value != null && value.matches("[0-9]{9}");
if (isValid) {
int check = 0;
for ( int index = 0; index < 3; index++ ) {
int pos = index * 3;
check += getNumericValue(value.charAt(pos)) * 3;
check += getNumericValue(value.charAt(pos + 1)) * 7;
check += getNumericValue(value.charAt(pos + 2));
}
isValid = check != 0 && check % 10 == 0;
}
return isValid;
}
}
RoutingNumberValidatorTest:
public class RoutingNumberValidatorTest {
private List<String> validRoutingNumbers = Arrays.asList("122105155", "082000549");
private List<String> invalidRoutingNumbers = Arrays.asList("1232101155", "032000549");
#Test
public void isValid() throws Exception {
RoutingNumberValidator routingNumberValidator = new RoutingNumberValidator();
validRoutingNumbers.forEach(it-> assertThat(routingNumberValidator.isValid(it)).as("Invalid Routing Number should not be valid %s", it).isTrue());
invalidRoutingNumbers.forEach(it-> assertThat(routingNumberValidator.isValid(it)).as("Invalid Routing Number should not be valid %s", it).isFalse());
}
}

I know this question is old and is already answered many times, but this answer from BrainJar is quite concise and works perfectly. So I thought I'd share.
validateRoutingNumber(num: string) {
// Run through each digit and calculate the total.
let n = 0;
for (let i = 0; i < num.length; i += 3) {
n += parseInt(num.charAt(i), 10) * 3
+ parseInt(num.charAt(i + 1), 10) * 7
+ parseInt(num.charAt(i + 2), 10);
}
// If the resulting sum is an even multiple of ten (but not zero),
// the aba routing number is good.
if (n != 0 && n % 10 == 0) {
return true;
} else {
return false;
}
}

and here is for python:
def validate_routing_number(routing_number):
# quick easy validations
if routing_number is None or routing_number == '':
return False
invalid_routing_message = 'invalid routing number'
if not re.match(r'^[0-9]{9}$', routing_number):
return False
# here is the more complicated validation!
checksum = int(routing_number[-1]) # last digit
sum = 0 # http://en.wikipedia.org/wiki/Routing_transit_number
sum += 7 * (int(routing_number[0])+int(routing_number[3])+int(routing_number[6]))
sum += 3 * (int(routing_number[1])+int(routing_number[4])+int(routing_number[7]))
sum += 9 * (int(routing_number[2])+int(routing_number[5]))
mod = sum % 10
return checksum != mod

package RoutingNumberAlgo;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
int checksum = 0, len = 0, sum = 0, mod = 0, rem = 0;
Scanner ss = new Scanner(System.in);
System.out.print("Enter the Routing Number: ");
String s = ss.nextLine();
len = s.length();
if (len != 9) {
System.out.print("Length not 9");
} else {
String newString = s.substring(s.length() - 1);
checksum = Integer.parseInt(newString);
sum = (3 * (Integer.parseInt("" + s.charAt(0)))) + (7 * (Integer.parseInt("" + s.charAt(1))))
+ (1 * (Integer.parseInt("" + s.charAt(2)))) + (3 * (Integer.parseInt("" + s.charAt(3))))
+ (7 * (Integer.parseInt("" + s.charAt(4)))) + (1 * (Integer.parseInt("" + s.charAt(5))))
+ (3 * (Integer.parseInt("" + s.charAt(6)))) + (7 * (Integer.parseInt("" + s.charAt(7))));
mod = 10 - (sum % 10);
if (mod == checksum)
System.out.print("True");
else
System.out.print("False");
;
}
}
}