Sudoku Code Program - Checking Rows,Columns, and Boxes - java

I need help checking rows, columns, and boxes for a Sudoku program. I am a high school student that needs help completing this project. If any one could provide help that would be awesome! I am currently working on checking boxes where I have a comment saying "Start Here". Thanks!
import java.util.*;
public class Run
{
Scanner scanner = new Scanner(System.in);
public static void main(String[] args)
{
char [][] board = new char [9][9];
Scanner scanner = new Scanner(System.in);
System.out.println("Welcome to Sudoku!\n");
fill(board);
printBoard(board);
inputLengthandDigits(board);
System.out.println();
printBoard(board);
}
public static void fill(char[][] arr){
for(int row = 0; row < arr.length; row++){
for(int col= 0; col< arr[row].length; col++){
arr[row][col] = '-';
}
}
}
public static void printBoard(char [][] array)
{
for(char[] row: array)
{
for(char play: row)
{
System.out.print(play+ " ");
}
System.out.println();
}
}
public static void inputLengthandDigits(char[][] array){
Scanner in = new Scanner(System.in);
for (int i = 0; i < 9; i++)
{
System.out.println("\nEnter the numbers in row " + (i+1) + ":");
String input = in.nextLine();
String numbers = "123456789-";
boolean numberscheck = false;
boolean endCheck = true;
boolean onlyOnce = true;
//Input Validation Starts Here!
//Checks if Input is only digits 0-9
do{
if(endCheck==false){
System.out.println("\nPlease input numbers only (1-9)!");
input = in.nextLine();
}
if(onlyOnce==false){
System.out.println("\nPlease input numbers only once!");
input = in.nextLine();
}
//Checks Length of User Input
while(input.length() < 9 || input.length() > 9){
System.out.println("\nPlease input 9 numbers!");
input = in.nextLine();
}
//Start Here
for(int a = 0; a<input.length()-1; a++){
for(int b= a + 1; b<input.length(); b++){
if(input.charAt(a)==input.charAt(b)){
onlyOnce = false;
}
}
}
for(int x = 0; x < input.length(); x++){
char thing = input.charAt(x);
numberscheck = false;
for(int y = 0; y < numbers.length(); y++){
char numbersn = numbers.charAt(y);
if(thing == numbersn){
numberscheck = true;
endCheck = true;
break;
}
}
if(numberscheck == false){
endCheck = false;
break;
}
}
}while(endCheck==false || onlyOnce==false);
for(int j=0; j<9; j++){
array[i][j] = input.charAt(j);
}
}
}
}

My initial response is too long for a comment. I'm not sure I have a solution to your problem, largely because you haven't actually pointed out which bit is a problem yet, but these pointers should help improve things anyway:
Please reformat your code. It is actually quite painful to look at. Spaces should be used consistently around variables, key words, brackets and operands. Opening curly braces should be on the same line as the method signature, for() loop or whatever else comes first. You have random blank lines within methods which don't separate logical sections so are just confusing. The compiler won't care about any of this, but if you can make your code look neater people will instinctively presume you care and are more likely to credit you with the ability to write decent code.
You have declared a new scanner variable three times. This is redundant and wasteful clutter. Either have a single, class-wide scanner, or (preferably), only create a scanner in a method which actually uses it and then remember to call scanner.close() once the scanner is no longer required.
inputLengthandDigits is a weird name. Is 'Lengthand' a single word, or should it be 'inputLengtHandDigits' or 'inputLengthAndDigits'? In camel case, capitalise every word except the first to make the whole easier to read. Whatever it should be, I don't understand from the name what this method does. It isn't inputting anything, it's getting inputs from someone else. Perhaps getData or populateGrid might be more explanatory.
9 appears quite a few times, with no explanation. I know where it came from, because I spend far too much time playing Sudoku, but it is a magic number and these are to be avoided at all costs. I met a magic number in the workplace once, wasted half a day trying to do what could have been a ten minute job if colleagues had recorded what the number was and where it came from. Here, just have a private static final int maxNumber = 9; statement.
A good thing: your main() method has almost no fiddly details in it. You have effectively used method calls to tell a story and describe what is happening elsewhere. This is a really, really good thing to do :)
Some of your logic tests can be tidied up a bit, e.g. !onlyOnce is the same as onlyOnce == false, and input.length() < maxNumber || input.length() > maxNumber can be simplified to input.length() != maxNumber. It's exactly the same logic, but faster to type and easier to read :)
It looks like your code under the //Start here comment is checking that you don't have any duplicate numbers. If you do get duplicate numbers, the program is still going to try and run the next bit of code before asking the user for alternative input. Is that something you want to happen, or a waste of time?
I actually burst out laughing when I saw a variable called 'thing'. Please, find a name which actually describes the purpose of this variable.
I have now run the code, and it rightly pointed out an error when I tried to key in duplicate numbers for row 4. However, it's now stuck there and keeps asking me to try again even when I put in a valid set of digits. This needs to be fixed. Look closely at which flags are triggering the request to retry. Run your code in debugging mode (you are using an IDE like IntelliJ or Eclipse, aren't you?) and deliberately enter a bad row to see the behaviour for yourself and where the logic is going wrong.
This whole method to get the row input, validate it, and then populate the array, is very big and confusing. You need to refactor it into a lot of smaller methods. Here is a suggestion to play with:
private static char[][] populateGrid(char[][] array) {
Scanner scanner = new Scanner(System.in);
for (int i = 0; i <maxNumber; i++) {
String rowData = getRowInput(scanner);
populateRow(array, rowNumber, rowData);
}
scanner.close;
return array;
}
private static String getRowInput(Scanner scanner) {
System.out.println("\nEnter the numbers in row " + (i + 1) + ":");
String input = scanner.nextLine();
while (!isValidInput(input) {
System.out.println("Please enter only the digits 1-9 in any order, with no duplicates or omissions");
input = scanner.nextLine();
}
return input;
}
private static boolean isValidInput(String input) {
if (!rightLengthOfInput(input)) {
return false;
}
if (!allUniqueDigits(input)) {
return false;
}
if (!usesCorrectCharacters(input)) {
return false;
}
return true;
}
I'll leave you to make the different input validation methods. It will largely be a case of moving your existing code, but the method names will help humans understand what each section is doing. This structure also allows you to cleanly add more validation checks, should such a thing be desired in the future.
Things to consider after all that:
Are you going to check that you have a viable Sudoku solution, or will you trust the user to put in correct data such that the columns also have each of the nine digits in them? How will you handle an invalid grid, e.g. each row is identical?
How far does this assignment want you to go? Do you need to systematically remove numbers to get a solvable puzzle rather than a completed grid? Will the assignment stop at a puzzle which can be seen in the console, or do you need a printable format, or will the user be able to play through the program? If the latter option, will this be in the console or using a graphical interface?
I appreciate that there is a lot to think about and work on here. Take it steadily, one step at a time, and keep asking questions if you need too.

Related

A method that I wrote with a scanner class doesn't seem to end

I wrote a method in order to get the choice of the user for the size of a grid. However, my code doesn't seem to work after executing the method, as it continues to run without end after I type in the response to console (if it matters, I am on repl.it). What is the issue with the code that prevents it from ending?
public static String createSize() {
int count = 0;
String answer = "";
Scanner sc = new Scanner(System.in);
System.out.println("How big do you want the grid? (Sizes: 4x4, 5x5, 6x6)");
String size = sc.nextLine();
//Checks if user-inputted answer matches possible answers
while (count < 1) {
if (size.equals("4x4") || size.equals("5x5") || size.equals("6x6")) {
count++;
answer = sc.nextLine();
}
else {
System.out.println("That was not a viable size. Please type a viable size.");
size = sc.nextLine();
}
}
sc.close();
return answer;
}
In the first If check in the while loop
Change
answer = sc.nextLine();
to
answer = size;
since u do not want the user to input size twice.
Your code should work fine now.
Let me know if anything isn't clear so I can modify and elaborate further
what's the main problem? I tried to run this code on all possible test cases and I didn't get any problem.
In the if statement you have answer = sc.nextLine(); which will again ask you for the input that's why the program was not executing further. If you pass input second time only then it will execute. Further in if statement answer wasn't assigned any value so even after entering two values it will not return anything.
Correction :-
if (size.equals("4x4") || size.equals("5x5") || size.equals("6x6")) {
count++;
answer = size;
}

How to create a loop for

I need to create a loop that adds "o" after each consonant
I am going to walk you through what I corrected and changed in your code to make it work in order to make it quick and easy for you to comprehend why your code doesn't work and why my answer fixes it.
The mistakes you made are basic ones and frankly you shouldn't have to much of a hard time correcting them yourself if you would use a debugger that walks you step by step in how your code works. You should look on how to use a debugger (for example the debugger used in Eclipse, hopefully you are using an IDE to make your life easier).
Firstly, when you are looking for a consonant in your code, you are only walking through the half of it because of your condition for(int x = 0; x<20; x++) since your string holding the consonants if of a length of 40 characters. This means you are missing consonants like the letter s.
Then you are correctly the consonants you find according to your Swedish language game. But you are never handling characters that are not of these found consonants. You should make a case where you handle these "non consonant" letters, may they be vowels or any kind of character (like punctuation marks and so on). I am fixing this with the use of a simple boolean here.
Keep in mind that my goal here is to change your code as little as I can, thus I went for adding a boolean to handle your cases (checking the presence of a consonant). There are, obviously, many other ways to implement what you are trying to do.
Here come the changes you should add to your code:
/*This comes after your print "På rövarspråk:"*/
boolean isConsonant = false; //Boolean to check wether there is a consonant or not
for(int i = 0; i<length; i++) {
//You didn't go through the whole consonants list you made with your prevision condition
for(int x = 0; x<consonants.length; x++){
if(array[i] == consonants[x])
{
isConsonant = true; //Set the boolean accordingly
String add = array[i]+"o"+array[i];
slang = slang + add;
break;
}
}
if(!isConsonant){ //If we don't have a consonant, add the char to the result string
slang += array[i];
}
isConsonant = false; //Reset the boolean for the next character
}
/*Here you can print the result (slang) if you want, as you did*/
so the idea is to dublicate consonants and put "o" between them, like t becomes tot, s becomes sos. Vocals are just copied. So you need a method that tells you if a given character is a vocal or consonant to base your decision on that.
public static boolean isConsonant(char inputChar){
final String consonantsx = "bBcCdDfFgGhHjJkKlLmMnNpPqQrRsStTvVwWxXzZ";
char consonants[] = consonantsx.toCharArray(); // String to charr
for(int i=0; i < consonants.length;i++){
if(inputChar == consonants[i]){ //note that in Strings u use the equals method instead of "=="
return true;
}
}
return false;
}
Given this method you can use it in the "translator method".
public String rovarSpraket(String normalString) {
char[] array = normalString.toCharArray(); // Input to a char array
System.out.println("På rövarspråk:");
String slang = "";
for (int i = 0; i < normalString.length(); i++) {
String add = "" + array[i];
if(Goran.isConsonant(array[i])){
add += "o" + array[i];
}
slang += add;
}
return slang;
}
This translates stubborn to sostotubobboborornon like in the wikipedia article https://en.wikipedia.org/wiki/R%C3%B6varspr%C3%A5ket.

Arrays - square-free word

This is what the program should do:
The word, zatabracabrac, is not square free, since it has subword, abrac twice start-
ing at position 4 of the word.
We are not allowed to use strings, breaks or other complex stuff. I get the square and square not part but am unable to find its place. I think I went wrong some place like I can't figure it out.
public static void main(String[] args) {
// part (a) of the main
Scanner keyboard = new Scanner(System.in);
System.out.println("***************************");
System.out.println(" Part (a)");
System.out.println("***************************");
do{
System.out.println("Enter a word and then press enter:");
String str=keyboard.next();
char[] word = str.toCharArray();
isSquareFree(word);
System.out.println("Do you want to test another word? Press y for yes, or another key for no");
}while(keyboard.next().charAt(0)=='y');
public static void isSquareFree(char[] word){
int z = 0;
for(int i=0; i<word.length; i++){
for(int j=0; j<word.length-1;j++){
if (word[j] == word[j+1]){
z = 1;
j = word.length;
}
else{
z = 2;
}
}
}
if (z == 1){
System.out.println();
System.out.println("Not Square Free");
}
else{
System.out.println();
System.out.println("Square Free");
}
}
}
Downvotes on the question: this is not where you solve your homework... we all went through having homeworks and solved them (well, most of us), and that's partly why we're capable of helping you.
You're checking whether the word contains two consecutive characters which are the same.
That's not what you want, try another solution.
Here's why it does what I said above:
The outer for loop doesn't have an effect on the inner one, since i is not used inside
Index j and j+1 in the same iteration as a character and the next one
Other notes:
j = word.length is the same as break here, try using that, it stops your loop like the end condition was satisfied; read more: http://docs.oracle.com/javase/tutorial/java/nutsandbolts/branch.html
For easier testing, you might want to use another main function containing only calls like isSquareFree("zatabracabrac".toCharArray());, even multiple ones to see multiple test results at once
This will greatly reduce the change-compile-run-check cycle's length.
You can use a debugger in an IDE (Eclipse or IntelliJ) to see what your program does.
Without debugging you can use println/print/printf calls to see how many iterations you have and what your values during those iterations.
Hints on solution:
As I see you're essentially looking for consecutive k-length subword duplicates
You phrased it right in the comment, the arbitrary length is giving it another level
At each position i try to look for a subword with length k which has a corresponding match starting at i + k (this helps the consecutive constraint)
k can be anything between a letter and half of the string (more than that is overkill since it cannot repeat twice)
I didn't code it, but it would be my first try
In your examples:
borborygmus
^=>
i
borborygmus
^=>
i+k
With k = 3 there is a match
zatabracabrac
^===>
i
zatabracabrac
^===>
i+k
With k = 5 there is a match

Java text analysis program

The following requisites are those for the program I'm currently having an issue with:
The program must be able to open any text file specified by the user, and analyze the frequency of verbal ticks in the text. Since there are many different kinds of verbal ticks (such as "like", "uh", "um", "you know", etc) the program must ask the user what ticks to look for. A user can enter multiple ticks, separated by commas.
The program should output:
the total number of tics found in the text
the density of tics (proportion of all words in the text that are tics)
the frequency of each of the verbal tics
the percentage that each tic represents out of all the total number of tics
My program is working very well, but what I basically need to do is that I must use separate methods for each component of the analysis. So I think the idea is that I need to split up the program in a few parts, which I have done by using the comments // because I'm basically having problems determining which type I should return, I know the last part (// public static void output(){)
should definitely be void because it returns nothing and only prints out.
public static void main(String[] args) throws FileNotFoundException {
double totalwords = 0; // double so density (totalwords/totalticks) returned can be double
int totalticks = 0;
System.out.println("What file would you like to open?");
Scanner sc = new Scanner(System.in);
String files = sc.nextLine();
Scanner input = new Scanner(new File(files));
// public static int[] initialise()
System.out.println("What words would you like to search for? (please separate with a comma)");
String ticks = sc.nextLine();
ticks = ticks.toLowerCase();
String[] keys = ticks.split(",");
int[] values = new int[keys.length];
// public static int[] processing(){?
for (int z=0; z<keys.length; z++){
values[z] = 0;
}
while (input.hasNext()){
String next = input.next();
totalwords++;
for (int x = 0; x<keys.length; x++){
if (next.toLowerCase().equals(keys[x])){
values[x]+=1;
}
}
}
for (Integer u : values) {
totalticks += u;
}
//public static void output(){
System.out.println("Total number of tics :"+totalticks);
System.out.printf("Density of tics (in percent): %.2f \n", ((totalticks/totalwords)*100));
System.out.println(".........Tick Breakdown.......");
for (int z = 0; z<keys.length; z++){
System.out.println(keys[z] + " / "+ values[z]+" occurences /" + (values[z]*100/totalticks) + "% of all tics");
}
}
Essentially the problem I'm having is the scope of the variables because Eclipse (my IDE) no longer recognizes the variables within each method once I get them out of comments - I know I need to use some static variables but would really like a hand as to how I could hook my program up together using methods.
Thanks a bunch,
M
You should do an object (class) decomposition. First ask the question "What objects do I have". (At a quick glance you might have "Text" and "Ticks" objects. You then want to see what methods you want to use for each object. For example in Text have countTicks(Ticks). Conotinue in this fashion to decompose your program.
First, please indent your code more consistently, with the first line of a block three spaces farther to the right, such as
for(...) {
//Do stuff
if(...) {
//Do stuff
}
}
It is hard to read what you've posted (luckily someone spruced it up for you!).
Consider re-writing your program from scratch, instead of trying to fix what you already have. Your current knowledge of the problem should allow you to recreate it pretty quickly. You will probably be able to cut and paste bits and pieces from your original code as well.
How about starting small, with something like
Scanner sc = getInputScannerFromUserInput();
private static final Scanner getInputScannerFromUserInput() {
System.out.println("What file would you like to open?");
return new Scanner(System.in);
}
and just go from there. Bit by bit. Good luck!

Inifnite loop while reading numbers

Basically I am trying to write a program that will read a finite set of values from the user then print the average. (I know how to do the calculations so I will leave those out.)
I am having a problem with the logic side of the loop.
I understand that everyone here would prefer that I attempted it but I am new to loops and I am having extreme difficulties understanding loop logic.
I am attempting to do this assignment for my class but the teacher is flying through material and does not help at all when questions are asked. When I ask for help with a problem he says do your best to attempt it and I will grade it accordingly?
I honestly do not know where to start.
import java.util.Scanner;
public class P4Point5 {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
String Status = "";
int count = 0;
while (in.hasNext()) {
count++;
}
for (int i = 0; i < count; i++) {
//Do calculations here?
}
}
}
You never get the next element:
while (in.hasNext())
count++;
You are always on the 1st element and asking if there is a 2nd element.
You should use:
while (in.hasNext())
int next = sc.nextInt();
BTW: please avoid statement without curly brackets. It is the root of all evil.
When you read for the first time, you don't read anymore, so hasNext() will stay always true since there will always be next element, which is.. the current element you're reading.
One solution is to do something like that:
String input = null;
while((input = in.next()) != null) {
//...
}
You can try this:
while (in.nextInt() != 'SOME INT TO STOP LOOP')
count++;
Instead of verify every time if we have an entered number, we can verify if the entered number is an stop condition.

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