For this java program, I'm trying to use a binary search for the array I have created in the Class Numbers, however, when I enter the 4th choice, the program just ends. The method binSearch is in Class Numbers. I can enter the required the size of the array, generate random numbers, search for specific numbers, and display them. However, when I want to use a binary search, the program ends as previously said. What is the reason why the program ends and what needs to be done to fix that certain method?
public class Numbers {
int[] array;
private int sizeOfArray;
public Numbers() {
sizeOfArray = 0;
array= new int [sizeOfArray];
}
public Numbers(int sizeOfArray) {
this.sizeOfArray = sizeOfArray;
array= new int [sizeOfArray];
}
public void generateNumbers() {
Random randomNumber = new Random();
int theNumber = 0;
for (int i = 0; i < sizeOfArray; i++) {
theNumber = randomNumber.nextInt(50);
array[i] = theNumber;
}
}
public int count(int num) {
int theNumbers = 0;
for (int i = 0; i < sizeOfArray; i++) {
if (array[i] == num) {
theNumbers++;
}
}
return theNumbers;
} // end count method
public String toString() {
String myArray = "";
for (int i = 0; i < sizeOfArray; i++) {
myArray += array[i] + " ";
}
return myArray;
}
public int binSearch(int[] array, int key) {
int low = 0;
int high = sizeOfArray - 1;
//int middle = (low + high + 1) /2;
int location = -1;
while (high >= low) {
int middle1 = (low + high) / 2;
if (array[middle1] == key ) {
//return true;
}
if (array[middle1] < key) {
low = middle1 + 1;
}
if (array[middle1] > key) {
high = middle1 - 1;
}
}
//return false;
return location;
}
}
and here is the main menu:
boolean isDone = false;
String input = null;
Numbers theNumber = new Numbers();
Scanner scanner = new Scanner (System.in);
try {
while (isDone == false) {
/*Menu options */
System.out.println("Enter 1 to create array size");
System.out.println("Enter 2 to generate random numbers");
System.out.println("Enter 3 to search and display number of occurrences");
System.out.println("Enter 4 to binary search to find whether specific number exists");
System.out.println("Enter 5 to display the array");
System.out.println("Enter 6 to quit the program");
input = scanner.nextLine();
switch (input) {
case "1":
int intNumber1 = 0;
System.out.println("Enter required size:");
intNumber1 = Integer.valueOf(scanner.nextLine());
theNumber = new Numbers(intNumber1);
System.out.println("Array has been generated.");
break;
case "2":
//theNumber = new Numbers();
theNumber.generateNumbers();
System.out.println("Numbers have been generated and stored.");
break;
case "3":
int intNumber2 = 0;
System.out.println("Enter number to search for: ");
intNumber2 = Integer.valueOf(scanner.nextLine());
System.out.println("Number of occurences of " + intNumber2 + " in the array is " + theNumber.count(intNumber2) + ".");
break;
case "4":
int key = 0;
theNumber.binSearch(null, key);
System.out.println("Array is sorted: ");
break;
case "5":
int theNumbers = 0;
if (theNumbers == 0)
{
System.out.println("No array has not been generated yet.");
}
else
{
System.out.println("The numbers are: ");
}
System.out.println(theNumber.toString());
break;
case "6":
isDone = true;
System.out.println("Bye... See you again");
scanner.close();
break;
default:
System.out.println("These are invalid choices...please reenter.");
break;
}
}
}
catch (Exception exception)
{
System.out.println("This is an invalid choice...please reenter.");
scanner.nextLine();
return;
}
Related
I am attempting to write a program that picks a random word from a text file, scrambles it, and allows the user to unscramble it by swapping 2 index locations at a time.
I have the program to the point where it grabs a random word from the text file and prints it out with the index numbers above it.
I am having trouble figuring out how to:
Get the word scrambled before it prints out on screen, and
How to get the user to be able to loop through swapping 2 indexes at a time until the word is unscrambled.
Is there a method I can write that will perform these actions?
Here is my code so far.
import java.io.*;
import java.util.*;
public class Midterm { // class header
public static void main(String[] args) { // Method header
int option = 0;
Scanner input = new Scanner(System.in);
int scrambled;
int counter = 0;
int index1;
int index2;
String[] words = readArray("words.txt");
/*
* Picks a random word from the array built from words.txt file. Prints
* index with word beneath it.
*/
int randWord = (int) (Math.random() * 11);
for (int j = 0; j < words[randWord].length(); j = j + 1) {
System.out.print(j);
}
System.out.print("\n");
char[] charArray = words[randWord].toCharArray();
for (char c : charArray) {
System.out.print(c);
}
/*
* Prompt the user for input to play game or quit.
*/
System.out.println("\n");
System.out.println("Enter 1 to swap a par of letters.");
System.out.println("Enter 2 to show the solution and quit.");
System.out.println("Enter 3 to quit.");
if (input.hasNextInt()) {
option = input.nextInt();
counter++;
}
else {
option = 3;
}
System.out.println("");
if (option == 1) {
System.out.println("Enter the two index locations to swap separated by a space. ");
index1 = 0;
index2 = 0;
if (input.hasNextInt()) {
index1 = input.nextInt();
}
else {
System.out.println("Please enter only numbers.");
}
if (input.hasNextInt()) {
index2 = input.nextInt();
}
else {
System.out.println("Please enter only numbers.");
}
}
}
// end main
public static String[] readArray(String file) {
// Step 1:
// Count how many lines are in the file
// Step 2:
// Create the array and copy the elements into it
// Step 1:
int ctr = 0;
try {
Scanner s1 = new Scanner(new File(file));
while (s1.hasNextLine()) {
ctr = ctr + 1;
s1.nextLine();
}
String[] words = new String[ctr];
// Step 2:
Scanner s2 = new Scanner(new File(file));
for (int i = 0; i < ctr; i = i + 1) {
words[i] = s2.next();
}
return words;
} catch (FileNotFoundException e) {
}
return null;
}
}
I made some pretty major modifications to your code, including adding a scrambler method. The program is almost perfect, its just that your file "words.txt" can not hold words with repeat letters. For example, yellow, green, and purple won't unscramble correctly, but white, gray, blue, orange, or red will work fine. Other than that, the program works well. It chooses a random word, then when it is solved, chooses a different word, changing the last word to null, so it does not get picked again. Here's the program:
import java.io.*;
import java.util.*;
public class Experiments { // class header
private static String[] words = readArray("/Users/UserName/Desktop/words.txt"); //change to your location of the file
public static void main(String[] args) { // Method header
int option = 0;
Scanner input = new Scanner(System.in);
int counter = 0;
String scrambledWord;
int index1;
int index2;
Random rand = new Random();
int randWord = rand.nextInt(words.length);
for (int j = 0; j < words[randWord].length(); j += 1) {
System.out.print(j);
}
System.out.print("\n");
scrambledWord = scrambler(words[randWord]);
System.out.println(scrambledWord);
System.out.println("\n");
System.out.println("Enter 1 to swap a pair of letters.");
System.out.println("Enter 2 to show the solution and quit.");
System.out.println("Enter 3 to quit.");
option = input.nextInt();
if (option == 1) {
while (!scrambledWord.equals(words[randWord])) {
index1 = 0;
index2 = 0;
boolean validOption = false;
System.out.println("Enter the two index locations to swap separated by a space.");
while (!validOption) {
if (input.hasNextInt()) {
index1 = input.nextInt();
index2 = input.nextInt();
validOption = true;
}
else {
System.out.println("Please enter only numbers.");
validOption = false;
break;
}
}
String letter1 = scrambledWord.substring(index1, index1+1);
String letter2 = scrambledWord.substring(index2, index2+1);
System.out.println("replacing " + letter1 + " with " + letter2 + "...");
if (index1 < index2) {
scrambledWord = scrambledWord.replaceFirst(letter2, letter1);
scrambledWord = scrambledWord.replaceFirst(letter1, letter2);
} else {
scrambledWord = scrambledWord.replaceFirst(letter1, letter2);
scrambledWord = scrambledWord.replaceFirst(letter2, letter1);
}
System.out.println();
for (int j = 0; j < words[randWord].length(); j += 1) {
System.out.print(j);
}
System.out.println("\n"+scrambledWord);
System.out.println();
counter++;
if (scrambledWord.equals(words[randWord])){
System.out.println("You did it! The word was " + words[randWord]);
System.out.println("You got it with " + counter + " replacements!");
words[randWord] = null;
if (words.length == 0){
System.out.println("I'm all out of words. You win!");
System.exit(0);
} else {
main(args);
}
}
}
} else if (option == 2) {
System.out.println(words[randWord]);
System.exit(0);
} else {
System.exit(0);
}
input.close();
}
//scrambles the word given to it
private static String scrambler(String word) {
String scrambled = "";
Random rand = new Random();
int length;
int index;
String letter;
String firststring;
String secondstring;
while (word.length()>0) {
length = word.length();
index = rand.nextInt(length);
letter = word.substring(index, index+1);
firststring = word.substring(0, index);
secondstring = word.substring(index+1);
word = firststring + secondstring;
scrambled += letter;
}
return scrambled;
}
public static String[] readArray(String file) {
int ctr = 0;
try {
Scanner s1 = new Scanner(new File(file));
while (s1.hasNextLine()) {
ctr = ctr + 1;
s1.nextLine();
}
String[] words = new String[ctr];
// Step 2:
Scanner s2 = new Scanner(new File(file));
for (int i = 0; i < ctr; i = i + 1) {
words[i] = s2.next();
}
return words;
} catch (FileNotFoundException e) {
e.printStackTrace();
}
return null;
}
}
And here's the list of words in the file words.txt(I pretty much wrote down whatever popped into my head that did not have repeat letters):
orange
red
brown
black
white
blue
tiger
horse
bugs
stack
overflow
pathfinder
extra
zealous
wisdom
under
above
death
life
second
first
frost
forest
These are obviously not the only words that can go in, you can add as many as you want, as long as they do not have 2 occurrences of the same letter.
You are reading the file incorrectly. Do
public static String[] readArray(String file) {
int ctr = 0;
try {
Scanner s1 = new Scanner(new File(file));
while (s1.hasNext()) {
ctr = ctr + 1;
s1.next();
}
//..rest of code
import java.util.Scanner;
import javax.swing.JOptionPane;
public class Hangman {
public static void main(String[] args) {
String playAgainMsg = "Would you like to play again?";
String pickCategoryMsg = "You've tried all the words in this category!\nWould you like to choose another category?";
int winCounter = 0, loseCounter = 0, score = 0;
String[] words;
int attempts = 0;
String wordToGuess;
boolean playCategory = true, playGame = true;
int totalCounter = 0, counter;
while (playCategory && playGame)
{
while (playCategory && playGame) {
words = getWords();
counter = 0;
while (playGame && counter < words.length) {
wordToGuess = words[counter++];
if (playHangman(wordToGuess)) {
winCounter++;
System.out.println("You win! You have won " + winCounter + " game(s)." + " You have lost " + loseCounter + " game(s).");
} else {
loseCounter++;
System.out.println("You lose! You have lost " + loseCounter + " game(s)." + " You have won " + winCounter + " game(s).");
}
if (counter < words.length) playGame = askYesNoQuestion(playAgainMsg);
}
if (playGame) playCategory = askYesNoQuestion(pickCategoryMsg);
}
}
}
public static boolean playHangman(String wordToGuess) {
String[] computerWord = new String[wordToGuess.length()];
String[] wordWithDashes = new String[wordToGuess.length()];
for (int i = 0; i < computerWord.length; i++) {
computerWord[i] = wordToGuess.substring(i, i+1);
wordWithDashes[i] = "_";
}
Scanner in = new Scanner(System.in);
int attempts = 0, maxAttempts = 7;
boolean won = false;
int points = 0;
while (attempts < maxAttempts && !won) {
String displayWord = "";
for (String s : wordWithDashes) displayWord += " " + s;
System.out.println("\nWord is:" + displayWord);
System.out.print("\nEnter a letter or guess the whole word: ");
String guess = in.nextLine().toLowerCase();
if (guess.length() > 1 && guess.equals(wordToGuess)) {
won = true;
} else if (wordToGuess.indexOf(guess) != -1) {
boolean dashes = false;
for (int i = 0; i < computerWord.length; i++) {
if (computerWord[i].equals(guess)) wordWithDashes[i] = guess;
else if (wordWithDashes[i].equals("_")) dashes = true;
}
won = !dashes; // If there are no dashes left, the whole word has been guessed
} else {
drawHangmanDiagram(attempts);
System.out.println("You've used " + ++attempts + " out of " + maxAttempts + " attempts.");
}
}
int score = 0;
score = scoreGame(attempts);
System.out.println("Your score is: " + score);
return won;
}
//should take in a failure int from the main method that increments after every failed attempt
public static void drawHangmanDiagram(int failure)
{
if (failure == 0)
System.out.println("\t+--+\n\t| |\n\t|\n\t|\n\t|\n\t|\n\t|\n\t|\n\t+--");
else if (failure == 1)
System.out.println("\t+--+\n\t| |\n\t| #\n\t|\n\t|\n\t|\n\t|\n\t|\n\t+--");
else if (failure == 2)
System.out.println("\t+--+\n\t| |\n\t| #\n\t| /\n\t|\n\t|\n\t|\n\t|\n\t+--");
else if (failure == 3)
System.out.println("\t+--+\n\t| |\n\t| #\n\t| / \\\n\t|\n\t|\n\t|\n\t|\n\t+--");
else if (failure == 4)
System.out.println("\t+--+\n\t| |\n\t| #\n\t| /|\\\n\t| |\n\t|\n\t|\n\t|\n\t+--");
else if (failure == 5)
System.out.println("\t+--+\n\t| |\n\t| #\n\t| /|\\\n\t| |\n\t| /\n\t|\n\t|\n\t+--");
else if (failure == 6)
System.out.println("\t+--+\n\t| |\n\t| #\n\t| /|\\\n\t| |\n\t| / \\\n\t|\n\t|\n\t+--");
}
// Asks user a yes/no question, ensures valid input
public static boolean askYesNoQuestion(String message) {
Scanner in = new Scanner(System.in);
boolean validAnswer = false;
String answer;
do {
System.out.println(message + " (Y/N)");
answer = in.nextLine().toLowerCase();
if (answer.matches("[yn]")) validAnswer = true;
else System.out.println("Invalid input! Enter 'Y' or 'N'.");
} while (!validAnswer);
return answer.equals("y");
}
public static boolean askForCategory(int category) {
Scanner in = new Scanner(System.in);
boolean validAnswer = false;
String answer;
do {
System.out.println("\nWould you like to play again? (Y/N)");
answer = in.nextLine().toLowerCase();
if (answer.matches("[yn]")) validAnswer = true;
else System.out.println("Invalid input! Enter 'Y' or 'N'.");
} while (!validAnswer);
return answer.equals("y");
}
// Asks the user to pick a category
public static String[] getWords() {
String[] programming = {"java", "pascal", "python", "javascript", "fortran", "cobol"};
String[] sports = {"gymnastics", "badminton", "athletics", "soccer", "curling", "snooker", "hurling", "gaelic", "football", "darts"};
String[] result = {""};
Scanner in = new Scanner(System.in);
boolean validAnswer = false;
String answer;
do {
System.out.println("Pick a category:\n1. Programming\n2. Sports");
answer = in.nextLine().toLowerCase();
if (answer.matches("[1-2]")) validAnswer = true;
else System.out.println("Invalid input! Enter the number of the category you want.");
} while (!validAnswer);
int selection = Integer.parseInt(answer);
switch (selection) {
case 1: result = randomOrder(programming); break;
case 2: result = randomOrder(sports); break;
}
return result;
}
// Sorts a String array in random order
public static String[] randomOrder(String[] array) {
int[] order = uniqueRandoms(array.length);
String[] result = new String[array.length];
for (int i = 0; i < order.length; i++) {
result[i] = array[order[i]];
}
return result;
}
// Generates an array of n random numbers from 0 to n-1
public static int[] uniqueRandoms(int n) {
int[] array = new int[n];
int random, duplicateIndex;
for (int i = 0; i < n; ) {
random = (int) (Math.random() * n);
array[i] = random;
for (duplicateIndex = 0; array[duplicateIndex] != random; duplicateIndex++);
if (duplicateIndex == i) i++;
}
return array;
}
public static int scoreGame(int attempts)
{
int score = 0;
switch (attempts)
{
case 0: score = 70; break;
case 1: score = 60; break;
case 2: score = 50; break;
case 3: score = 40; break;
case 4: score = 30; break;
case 5: score = 20; break;
case 6: score = 10; break;
case 7: score = 0; break;
}
return score;
}
}
I have got it working so that it keeps count of the games won and lost, as well as assigning a score based on the amount of attempts/lives saved but I haven't been able to find a way to get it to keep a total score for all of the games played. Each game unfortunately has a seperate score. If anyone can advise me on a way of doing this, it would be greatly appreciated.
Create an int totalScore variable where winCounter, loseCounter and score are defined. Then increment it after each call to scoreGame()
score = scoreGame(attempts);
totalScore += score;
System.out.println("Your score is: " + score);
If you want to permanently save statistics between sessions then it's a whole nother story. You would need to write your scores to a file after each round and then start your program by reading this score file. It's hardly impossible, but requires a bit more code.
I have code that first generates the array with 100 elements, then places randomly generated numbers in each element. I am trying to do a search for a number and if found, print out its index. the code I have so far is:
import java.util.Scanner;
public class Lab01
{
public static void main(String[] args)
{
int[] nums = new int[100];
for (int i = 0; i < nums.length; i++)
{
nums[i] = (int)((Math.random() * 100) + 1);
System.out.print(nums[i] + " , ");
}
System.out.println();
Scanner input = new Scanner(System.in);
int num;
System.out.println("What number would you like to search for?");
num = input.nextInt();
boolean found = false;
for (int i = 0; i < nums.length; i++)
{
if (num == nums[i])
{
found = true;
break;
}
if (found)
{
System.out.println("That number was found at index" + i);
break;
}
else
{
System.out.println("That number was not found.");
break;
}
}
}
}
I put in the print statements to see the values, so I could verify that it was working, but it ALWAYS returns "Not found". What am I missing here?
Try to replace this block, see the explanation in the bottom :
for (int i = 0; i < nums.length; i++)
{
if (num == nums[i])
{
found = true;
break;
}
if (found)
{
System.out.println("That number was found at index" + i);
break;
}
else
{
System.out.println("That number was not found.");
break;
}
With:
int i; // create this
for ( i = 0; i < nums.length; i++) // and remove int from for loop
{
if (num == nums[i])
{
found = true;
break;
}
}
if (found)
{
System.out.println("That number was found at index " + i);
}
else
{
System.out.println("That number was not found.");
}
Explanation:
Put out of for loop the both if condtion and remove the break statement from them and create a int i = 0 before the for loop like above.
You are breaking out of the loop after checking the first number, so if the first number doesn't match, you print "That number was not found". If the first number does match, you break without printing anything. You should only print "That number was not found" after checking all the numbers of the array.
Your if statement should come after the for loop, not inside it.
int i = 0;
for (; i < nums.length; i++) {
if (num == nums[i]) {
found = true;
break;
}
}
if (found) {
System.out.println("That number was found at index" + i);
} else {
System.out.println("That number was not found.");
}
Try this :)
public static void main(String[] args) {
int[] tab = {3, 2, 1, 7, 2, 1};
int userInput, i;
Integer index = null;
boolean found = false;
int counter = 0;
Scanner input = new Scanner(System.in);
System.out.println("Enter a number: ");
userInput = input.nextInt();
for (i = 0; i<tab.length; i++) {
if (tab[i] == userInput) {
found = true;
index = i;
counter++;
}
}
if (found == true) {
System.out.println("Found number: " + userInput + " at index " + index + " and number is found " + counter + " times in array");
} else {
System.out.println("Not found number: " + userInput);
}
}
public class Contains {
public static void main(String[] args) {
int[] num = {1, 2, 3, 4, 5};
int toFind = 3;
boolean found = false;
for (int n : num) {
if (n == toFind) {
found = true;
break;
}
}
if(found)
System.out.println(toFind + " is found.");
else
System.out.println(toFind + " is not found.");
}
}
Hey everyone so I am stuck on the last part of this program that I have been doing for an assignment. So generally I am given a large list of names and numbers that represent popularity ranks for names in certain decades. This is what the file looks like <----- this is a link to see the names.txt
So I created a method that sorts the list in a certain decade which is the getIndexOfSmallest and interchange. Every decade has two names that are ranked the same so between the years of 1900-1909 there are two names that are ranked 1, two names that are ranked 2, two names that are ranked 3 and so on. The last part of the program and the one I need help with is suppose to sort through the object array and find any decades where there is only one name for one rank or no names for a certain rank. The output will be sent to a file and it will look like this. <------ this is another link to see the expected output
This is what my code looks like. This is my Name code that creates the objects:
public class Name{
private String givenName;
private int[] ranks = new int[12];
public Name(String name, int[] popularityRanks){
givenName = name;
for (int i = 0; i < 11; i++){
ranks[i] = popularityRanks[i];
}
}
public String getName(){
return givenName;
}
public int getPop(int decade){
if (decade >= 0 && decade <= 10){
return ranks[decade];
}
else{
return -1;
}
}
public String getHistoLine(int decade){
String histoLine = ranks[decade] + ": ";
double popularity = (1000 - ranks[decade]) / 11.7;
int histo = (int)popularity;
if(popularity != 0){
for (int i = 0; i < histo; i++){
histoLine += "*";
}
}
return histoLine;
}
public String getHistogram(){
String histogram = "";
for (int i = 0; i < 11; i++){
histogram += this.getHistoLine(i) + "\n";
}
return histogram;
}
}
This is my NameApp which is where my main is at:
import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;
public class NameApp{
private static boolean validInput;
private static boolean stillWorking = true;
private static boolean validDecade;
private static boolean validName;
static Scanner keyboard = new Scanner(System.in);
// Main method
public static void main(String[] args) throws FileNotFoundException{
String[] nameArray = readNamesFile();
Name[] list = new Name[nameArray.length];
loadNames(list, nameArray);
char choice;
do {
do {
displayMenu();
choice = getUserInput();
} while (!validInput);
switch (choice){
case 'A':
displayHistogram(list);
break;
case 'B':
compareTwoNames(list);
break;
case 'C':
displayTopTenNames(list);
break;
case 'D':
writeAnomaliesToFile(list);
stillWorking = false;
break;
default:
break;
}
} while (stillWorking);
}
/*
* This method will read the file name names.txt and load the names and populations into a string array.
*/
private static String[] readNamesFile() throws FileNotFoundException{
String[] nameArray = new String[4429];
Scanner inputStream = null;
String fileName = "names.txt";
inputStream = new Scanner (new File(fileName));
int i = 0;
while (inputStream.hasNextLine()){
nameArray[i] = inputStream.nextLine();
i++;
}
inputStream.close();
return nameArray;
}
/*
* load names method will take a Name array and the string array from the readNamesFile method. This method will split the names and the population ranks and send them to the constructor in Name.java.
*/
private static void loadNames(Name[] list, String[] nameArray){
int length;
int spacePos;
int[] popRanks = new int[11];
String name;
String linePop;
for (int i = 0; i < nameArray.length; i++){
length = nameArray[i].length();
spacePos = nameArray[i].indexOf(" ");
name = nameArray[i].substring(0,spacePos);
linePop = nameArray[i].substring(spacePos + 1, length);
for (int j = 0; j < 11; j++){
popRanks[j] = Integer.parseInt(linePop.split(" ")[j]);
}
list[i] = new Name(name, popRanks);
}
}
/*
* displayMenu method will display the menu that the user will select their program function.
*/
private static void displayMenu(){
System.out.println("Enter the character corresponding to your selection:");
System.out.println("\ta - Print histogram for a name");
System.out.println("\tb - Compare two names in a decade");
System.out.println("\tc - Print top ten names for a decade");
System.out.println("\td - Quit (display file anomalies)");
}
/*
* getUserInput is a method that will accept a string input from the user it will send this string to two different helper methods.
*/
private static char getUserInput(){
String selection = keyboard.nextLine();
System.out.println(" Your selection: " + selection);
checkUserInput(selection);
char choice = stringToChar(selection);
return choice;
}
/*
* helper method: checkUserInput will accept the user input from getUserInput and test the input to see if the input is a valid input from the user. If it is not set the instance boolean variable to false if it is set it to true.
*/
private static boolean checkUserInput(String selection){
if (!selection.equalsIgnoreCase("a") && !selection.equalsIgnoreCase("b") && !selection.equalsIgnoreCase("c") && !selection.equalsIgnoreCase("d")){
System.out.println("Invalid input. Try again...");
return validInput = false;
}
else {
return validInput = true;
}
}
/*
* helper method: stringToChar method will take the input that the user entered after it has been tested to see if it is valid and this method will change the input to a character value. This will also make the character to an upper case letter.
*/
private static char stringToChar(String selection){
char choice = selection.charAt(0);
choice = Character.toUpperCase(choice);
return choice;
}
/*
* Menu option: A. This method will take a user input for the name they want and display the histogram for the selected name.
*/
private static void displayHistogram(Name[] list){
String nameInput;
String histogram;
int nameLocation;
do {
nameInput = nameEntry();
nameLocation = checkListArray(nameInput, list);
if (!validName){
System.out.println("The name, " + nameInput + ", was not found!");
}
} while (!validName);
histogram = list[nameLocation].getHistogram();
System.out.println("Histogram for name, " + list[nameLocation].getName() + ":");
System.out.println(histogram);
}
private static void compareTwoNames(Name[] list){
String nameOne;
String nameTwo;
String oneHistoLine;
String twoHistoLine;
int oneLocation;
int twoLocation;
int decade;
do {
nameOne = nameEntry();
oneLocation = checkListArray(nameOne, list);
if (!validName){
System.out.println("The first name, " + nameOne + ", was not found!");
}
} while (!validName);
do {
nameTwo = nameEntry();
twoLocation = checkListArray(nameTwo, list);
if (!validName){
System.out.println("The second name, " + nameTwo + ", was not found!");
}
} while(!validName);
decadeMenu();
decade = decadeSelection();
oneHistoLine = list[oneLocation].getHistoLine(decade);
twoHistoLine = list[twoLocation].getHistoLine(decade);
System.out.println("Data for " + list[oneLocation].getName());
System.out.println(" " + oneHistoLine);
System.out.println("Data for " + list[twoLocation].getName());
System.out.println(" " + twoHistoLine);
}
private static void displayTopTenNames(Name[] list){
int decade;
int count = 0;
int l = 0;
String[] decadeName = new String[20];
Name[] temp = new Name[list.length];
decadeMenu();
decade = decadeSelection();
for (int i = 0; i < list.length; i++){
temp[i] = list[i];
}
for (int index = 0; index < temp.length; index++){
int smallestIndex = getIndexOfSmallest(decade, index, temp);
interchange(decade, index, smallestIndex, temp);
}
do {
if (temp[l].getPop(decade) == 0){
l++;
}
else {
decadeName[count] = temp[l].getName() + " " + "(" + temp[l].getPop(decade) + ")";
count++;
l++;
}
} while (count < 20);
writeTopTen(decadeName, decade);
}
private static void writeAnomaliesToFile(Name[] list){
System.out.println("Terminating... but first the anomalies in the data file:");
checkAnomalies(list);
System.out.println("Anomalies written to anomalies.txt.");
}
private static String nameEntry(){
String nameInput = "";
System.out.println("Enter a name: ");
nameInput = keyboard.nextLine();
return nameInput;
}
private static int checkListArray(String nameInput, Name[] list){
int nameLocation = -1;
int listLength = list.length;
for (int i = 0; i < listLength; i++){
if (nameInput.equalsIgnoreCase(list[i].getName())){
validName = true;
return nameLocation = i;
}
}
if (nameLocation == -1){
validName = false;
return nameLocation;
}
return nameLocation;
}
private static void decadeMenu(){
System.out.println("Enter number correpsonding to your decade:");
System.out.println(" 1 - 1900-1909");
System.out.println(" 2 - 1910-1919");
System.out.println(" 3 - 1920-1929");
System.out.println(" 4 - 1930-1939");
System.out.println(" 5 - 1940-1949");
System.out.println(" 6 - 1950-1959");
System.out.println(" 7 - 1960-1969");
System.out.println(" 8 - 1970-1979");
System.out.println(" 9 - 1980-1989");
System.out.println(" 10 - 1990-1999");
System.out.println(" 11 - 2000-2005");
}
private static int decadeSelection(){
String decadeChoice;
int decade;
do {
System.out.println("Enter a decade: ");
decadeChoice = keyboard.nextLine();
decade = checkDecade(decadeChoice);
} while (!validDecade);
return decade;
}
private static int checkDecade(String decadeChoice){
int decade = 0;
try {
decade = Integer.parseInt(decadeChoice);
}
catch (Exception e){
System.out.println("That is not an integer. Please try again.");
validDecade = false;
return decade;
}
if (decade < 1 || decade > 11){
System.out.println("Enter an integer between 1 and 11");
validDecade = false;
return decade;
}
else {
validDecade = true;
decade = changeDecade(decade);
return decade;
}
}
private static int changeDecade(int decade){
int newDecade = 0;
switch (decade){
case 1:
newDecade = 0;
break;
case 2:
newDecade = 1;
break;
case 3:
newDecade = 2;
break;
case 4:
newDecade = 3;
break;
case 5:
newDecade = 4;
break;
case 6:
newDecade = 5;
break;
case 7:
newDecade = 6;
break;
case 8:
newDecade = 7;
break;
case 9:
newDecade = 8;
break;
case 10:
newDecade = 9;
break;
case 11:
newDecade = 10;
break;
default:
break;
}
return newDecade;
}
private static int getIndexOfSmallest(int decade, int startIndex, Name[] temp){
int min = temp[startIndex].getPop(decade);
int indexOfMin = startIndex;
for (int index = startIndex + 1; index < temp.length; index++){
if (temp[index].getPop(decade) < min){
min = temp[index].getPop(decade);
indexOfMin = index;
}
}
return indexOfMin;
}
private static void interchange(int decade, int i, int j, Name[] temp){
Name tempInt = temp[i];
temp[i] = temp[j];
temp[j] = tempInt;
}
private static String decadeYears(int decade){
String decadeYear = "";
switch (decade){
case 0:
decadeYear = "1900 - 1909";
break;
case 1:
decadeYear = "1910 - 1919";
break;
case 2:
decadeYear = "1920 - 1929";
break;
case 3:
decadeYear = "1930 - 1939";
break;
case 4:
decadeYear = "1940 - 1949";
break;
case 5:
decadeYear = "1950 - 1959";
break;
case 6:
decadeYear = "1960 - 1969";
break;
case 7:
decadeYear = "1970 - 1979";
break;
case 8:
decadeYear = "1980 - 1989";
break;
case 9:
decadeYear = "1990 - 1999";
break;
case 10:
decadeYear = "2000 - 2005";
break;
default:
break;
}
return decadeYear;
}
private static void writeTopTen(String[] decadeName, int decade){
String years;
years = decadeYears(decade);
System.out.println("Ten most popular names (male and female) during the decade " + years + " were:");
for (int i = 0; i < 20; i += 2){
System.out.printf("%20s\t%20s\n", decadeName[i],decadeName[i + 1]);
}
}
private static void checkAnomalies(Name[] list){
Name[] temp = new Name[list.length];
int anomalyCount = 0;
int popTwo = 0;
int popOne = 0;
String[] anomalies = new String[list.length];
for (int i = 0; i < list.length; i++){
temp[i] = list[i];
}
for (int decade = 0; decade < 11; decade++){
for (int index = 0; index < temp.length; index++){
int smallestIndex = getIndexOfSmallest(decade, index, temp);
interchange(decade, index, smallestIndex, temp);
}
int rank = 0;
for (int i = 1; i < temp.length - 1; i += 2){
popOne = temp[i].getPop(decade);
popTwo = temp[i+1].getPop(decade);
if (popOne != 0){
rank++;
}
if (popOne == rank && popTwo != rank){
String decadeYear = decadeYears(decade);
anomalies[anomalyCount] = "One name (" + temp[i].getName() + ") for " + decadeYear + ", rank " + temp[i].getPop(decade) + ".";
anomalyCount++;
}
else if (popOne != rank && popTwo == rank){
String decadeYear = decadeYears(decade);
anomalies[anomalyCount] = "One name (" + temp[i+1].getName() + ") for " + decadeYear + ", rank " + temp[i+1].getPop(decade) + ".";
anomalyCount++;
}
else if (popOne != rank && popTwo != rank){
String decadeYear = decadeYears(decade);
anomalies[anomalyCount] = "No names for " + decadeYear + ", rank " + temp[i].getPop(decade) + ".";
anomalyCount++;
}
}
}
}
}
This is the information provided by my professor:
There are 1,065 anomalies: in some cases, only one name with a particular rank in a decade or in other cases, no names in a decade with a particular rank. With 11 decades and 999 ranks to check, 1065 is only about 9.7% of the name-pairs that are broken or anomalous. There should be a pair of names for each rank (999) in each decade (11): this gives 10,989 name-pairs. Your code to do this will need to check each name in each decade for each rank in order to find all 1065 anomalies.
When I was debugging my program I saw that the ranks end on odd numbers. which is why I started my loop in checkAnomalies at 1 instead of 0 (considering that at 0 the names rank will be 0 and that is considered to be a name that was picked 1000 or less). When I run the program with:
String[] anomalies = new String[1065];
I get this error:
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 1065
at NameApp.checkAnomalies(NameApp.java:512)
at NameApp.writeAnomaliesToFile(NameApp.java:259)
at NameApp.main(NameApp.java:43)
and when I change my code to be:
String[] anomalies = new String[temp.length];
I get this error:
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 4429
at NameApp.checkAnomalies(NameApp.java:502)
at NameApp.writeAnomaliesToFile(NameApp.java:259)
at NameApp.main(NameApp.java:43)
I figure my error is in my loops but I can't figure out where.. I figured my loops are finding way more errors then their really is.. Just wondering if anyone can help me out with this.. It is really the only part that I need left. Thanks in advance
EDIT:
This is the relevant code for what I need help with:
private static void writeAnomaliesToFile(Name[] list){
System.out.println("Terminating... but first the anomalies in the data file:");
checkAnomalies(list);
System.out.println("Anomalies written to anomalies.txt.");
}
method that is called:
private static void checkAnomalies(Name[] list){
Name[] temp = new Name[list.length];
int anomalyCount = 0;
int popTwo = 0;
int popOne = 0;
String[] anomalies = new String[list.length];
for (int i = 0; i < list.length; i++){
temp[i] = list[i];
}
for (int decade = 0; decade < 11; decade++){
for (int index = 0; index < temp.length; index++){
int smallestIndex = getIndexOfSmallest(decade, index, temp);
interchange(decade, index, smallestIndex, temp);
}
int rank = 0;
for (int i = 1; i < temp.length - 1; i += 2){
popOne = temp[i].getPop(decade);
popTwo = temp[i+1].getPop(decade);
if (popOne != 0){
rank++;
}
if (popOne == rank && popTwo != rank){
String decadeYear = decadeYears(decade);
anomalies[anomalyCount] = "One name (" + temp[i].getName() + ") for " + decadeYear + ", rank " + temp[i].getPop(decade) + ".";
anomalyCount++;
}
else if (popOne != rank && popTwo == rank){
String decadeYear = decadeYears(decade);
anomalies[anomalyCount] = "One name (" + temp[i+1].getName() + ") for " + decadeYear + ", rank " + temp[i+1].getPop(decade) + ".";
anomalyCount++;
}
else if (popOne != rank && popTwo != rank){
String decadeYear = decadeYears(decade);
anomalies[anomalyCount] = "No names for " + decadeYear + ", rank " + temp[i].getPop(decade) + ".";
anomalyCount++;
}
}
}
}
Solved myself just had to sleep on it:
private static void checkAnomalies(Name[] list)
throws FileNotFoundException{
Name[] temp = new Name[list.length];
String[] anomalies = new String[1065];
int anomalyCount = 0;
for (int i = 0; i < list.length; i++){
temp[i] = list[i];
}
for (int decade = 0; decade < 11; decade++){
for (int ranks = 1; ranks < 1000; ranks++){
int found = 0;
String tempName = "";
String decadeYear = decadeYears(decade);
for (int i = 0; i < temp.length; i++){
if (temp[i].getPop(decade) == ranks){
found++;
}
if (found == 1 &&
temp[i].getPop(decade) == ranks){
tempName = temp[i].getName();
}
}
if (found == 0){
anomalies[anomalyCount] = "No names "
+ "for " + decadeYear + ", rank "
+ ranks + ".";
anomalyCount++;
}
else if (found == 1){
anomalies[anomalyCount] = "One "
+ "Name (" + tempName + ") for "
+ decadeYear + ", rank "
+ ranks + ".";
anomalyCount++;
}
}
}
writeAnomaliesFile(anomalies);
}
/*
* Helper method: this method will create and write
* each anomalies to a text document called
* anomalies.txt.
*/
private static void
writeAnomaliesFile(String[] anomalies)
throws FileNotFoundException{
String fileName = "anomolies.txt";
PrintWriter outputStream = null;
outputStream = new PrintWriter(fileName);
for (int i = 0; i < anomalies.length; i++){
outputStream.println(anomalies[i]);
}
outputStream.close();
}
This is very interesting, i notice. Before i can explain further its best i show the code and you will understand what i mean.
This is the code:
public class Qn3 {
static BigDecimal[] accbal = new BigDecimal[19];
private static Integer[] accnums = new Integer[19];
public static void main(String[] args) {
addaccount();
}
public static void addAccount() {
int i = 0, accno, input, j, check;
BigDecimal accbala;
DecimalFormat df = new DecimalFormat("0.00");
Scanner sc = new Scanner(System.in);
Scanner in = new Scanner(System.in);
accnums[1] = new Integer(1);
while (accnums.length >= count(accnums)) {
System.out.print("Enter the account number: ");
while (sc.hasNext("[0-9]{7}")) {
accno = sc.nextInt();
System.out.print("Enter account balance: ");
accbala = in.nextBigDecimal();
for (j = 0; j < accnums.length; j++) {
if (accnums[j] == null)
break;
else if (accnums[j].equals(accno)) {
break;
}
}
if (j == accnums.length) {
System.out.print("No more than 20 accounts can be added.");
} else if (accnums[j] != null) {
if ((accnums[j].equals(accno)))
System.out.println("Account already exists");
break;
} else {
accnums[j] = accno;
accbala = accbala.setScale(2, RoundingMode.HALF_UP);
accbal[j] = accbala;
check = j;
System.out.println("Current number of accounts in the system: "
+ (check + 1)
+ "\nNumber of accounts still can be added: "
+ (20 - (check + 1)));
}
}
while (!sc.hasNext("[0-9]{7}")) {
System.out.println("Wrong NRIC");
break;
}
while (accnums.length <= count(accnums)) {
System.out.println("20 accounts have already been created");
break;
}
break;
}
}
private static int count(Integer[] array) {
int count = 0;
// accnums = new Integer[] {1,2};
for (int index = 0; index < array.length; index++) {
if (array[index] != null) {
count++;
}
}
// System.out.println("You have used " + count + " slots");
return count;
}
}
So now that you have seen the code the problem that is hard to notice is this, take note of the line in the addaccount() method where
System.out.println("Current number of accounts in the system: "+(check+1)+"\nNumber of accounts still can be added: "+(20 - (check+1)));
this line the first check+1 will give me 1 then the next one gives me 3! and then the next time i run the method it gives me 4 and then again 5 and so on so forth, what is happening to 2?
You have that println in an else block, and when j == 1 you're hitting the else if case. Try removing this line
accnums[1] = new Integer (1);