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Java: How to use binary search with an array

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;
}

How to return a string?

import java.util.*;
public class HangManP5
{
public static void main(String[] args)
{
int attempts = 10;
int wordLength;
boolean solved;
Scanner k = new Scanner(System.in);
System.out.println("Hey, what's your name?");
String name = k.nextLine();
System.out.println(name+ ", hey! This is a hangman game!\n");
RandomWord(word);
int len = word.length();
char[] temp = new char[len];
for(int i = 0; i < temp.length; i++)
{
temp[i] = '*';
}
System.out.print("\n");
System.out.print("Word to date: ");
while (attempts <= 10 && attempts > 0)
{
System.out.println("\nAttempts left: " + attempts);
System.out.print("Enter letter: ");
String test = k.next();
if(test.length() != 1)
{
System.out.println("Please enter 1 character");
continue;
}
char testChar = test.charAt(0);
int foundPos = -2;
int foundCount = 0;
while((foundPos = word.indexOf(testChar, foundPos + 1)) != -1)
{
temp[foundPos] = testChar;
foundCount++;
len--;
}
if(foundCount == 0)
{
System.out.println("Sorry, didn't find any matches for " + test);
}
else
{
System.out.println("Found " + foundCount + " matches for " + test);
}
for(int i = 0; i < temp.length; i++)
{
System.out.print(temp[i]);
}
System.out.println();
if(len == 0)
{
break; //Solved!
}
attempts--;
}
if(len == 0)
{
System.out.println("\n---------------------------");
System.out.println("Solved!");
}
else
{
System.out.println("\n---------------------------");
System.out.println("Sorry you didn't find the mystery word!");
System.out.println("It was \"" + word + "\"");
}
}
public static String RandomWord(String word)
{
//List of words
Random r = new Random();
int a = 1 + r.nextInt(5);
if(a == 1)
{
word=("Peace");
}
if(a == 2)
{
word=("Nuts");
}
if(a == 3)
{
word=("Cool");
}
if(a == 4)
{
word=("Fizz");
}
if(a == 5)
{
word=("Awesome");
}
return (word);
}
}
Ok, so this is my code for a hangman game, the only thing I have left to do is to get my program to randomize one of the words, which it should do in the method successfully. But the only problem I'm having is getting the String variable "word" to go back to the main class (there are errors underlining all the "word" variables in the main class).
If I could get help with either this or another way to produce a random word from a list, that would be amazing.

In java, parameters are passed by value and not by reference. Therefore, you cannot change the reference of a parameter.
In your case, you need to do:
public static String getRandomWord() {
switch(new Random().nextInt(5)) {
case 0:
return "Peace";
case 1:
return "Nuts";
// ...
default:
throw new IllegalStateException("Something went wrong!");
}
}
And in main:
// ...
String word = getRandomWord();
int len = word.length();
// ...

You can't modify the caller's reference.
RandomWord(word);
needs to be something like
word = RandomWord(word);
Also, by convention, Java methods start with a lower case letter. And, you could return the word without passing one in as an argument and I suggest you save your Random reference and use an array like
private static Random rand = new Random();
public static String randomWord() {
String[] words = { "Peace", "Nuts", "Cool", "Fizz", "Awesome" };
return words[rand.nextInt(words.length)];
}
And then call it like
word = randomWord();

Encountering Error with Pig Code

My variable names are pretty stupid near the bottom but that's not the point. Line 110 says that I'm making an else statement without the if and I'm nearly certain the if is there. Please help in any way you can.
Thank you
import java.util.*;
public class hw7
{
public static void main(String[] args)
{
int turnScores = 0;
int totalScores = 0;
int turnScores2 = 0;
int totalScores2 = 0;
int dice;
int dice2;
String input = "r";
char repeat;
boolean peppers;
peppers = true;
Scanner keyboard = new Scanner(System.in);
Random randomNumbers = new Random();
System.out.println("Welcome to the game of Pig!\n");
while(totalScores < 20 || totalScores2 < 20)
{
do
{
dice = randomNumbers.nextInt(6) + 1;
System.out.println("You rolled: " + dice);
if(dice == 1)
{
turnScores = 0;
System.out.print("Your lose your turn!");
System.out.println("Your Total is " + totalScores);
break;
}
else
{
turnScores += dice;
System.out.print("Your turn score is " + turnScores);
System.out.println(" and your total scores is " + totalScores);
System.out.println("If you hold, you will have " + turnScores
+ " points.");
System.out.println("Enter 'r' to roll again, 'h' to hold.");
input = keyboard.nextLine();
repeat = input.charAt(0);
if(repeat == 'h')
{
break;
}
}
}
while(input.equalsIgnoreCase("r") || dice != 1);
totalScores += turnScores;
peppers = peppers(turnScores, turnScores2);
System.out.println("Your scores is " + totalScores);
turnScores = 0;
System.out.println();
System.out.println("It is the computer's turn.");
do
{
dice2 = randomNumbers.nextInt(6) + 1;
System.out.println("The computer rolled: " + dice2);
if(dice2 == 1)
{
turnScores2 = 0;
System.out.print("The computer lost its turn!");
System.out.println(" Computer total is " + totalScores2);
break;
}
else
{
turnScores2 += dice2;
if(turnScores2 >= 20 || (totalScores2 + turnScores2) >= 20 )
{
System.out.println("The computer holds");
break;
}
}
}
while(dice2 != 1 || turnScores2 < 20);
totalScores2 += turnScores2;
System.out.println("The computer's scores is " + totalScores2 + "\n");
turnScores2 = 0;
}
}
public static boolean peppers(int chili, int ghost)
{
boolean done;
done = true;
if(chili >= 20);
{
done = false;
System.out.println(" YOU WIN!!!");
return done;
}
else (ghost >= 20);
{
done = false;
System.out.println(" COMPUTER WINS");
return done;
}
/*else
{
return done;
}
*/
}
}

Try removing the semicolons in if(chili >= 20); and else (ghost >= 20);.

public static boolean peppers(int chili, int ghost)
{
boolean done;
done = true;
if(chili >= 20)
{
done = false;
System.out.println(" YOU WIN!!!");
}
else if (ghost >= 20)
{
System.out.println(" COMPUTER WINS");
}
return done;
}

replace
else (ghost >= 20);
with
else if (ghost >= 20)
and remove the semicolons after the if-statement.

Searching an object array for certain values

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();
}

Java skipping a number in the sequence

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);