I wasn't able to figure this one out since I don't know how to calculate "inserting" an underscore. I included my attempt at solving this problem.
Given a string, do not let the same character repeat for n positions. If it does repeat, insert an underscore to push
it X positions down. The final output needed is just the total number of characters.
Example 1) Input "QQ",2 becomes "Q__Q", the return value is 4.
Example 2) Input "ABCA",2 becomes "ABCA" (no spaces needed), total characters is 4.
Example 3) Input "DEDEE", 1 becomes "DEDE_E", total chars is 6.
Example 4) Input "JKJK", 2 becomes "JK_JK", total characters is 5 (The toughest example).
import java.lang.Math;
import java.util.HashMap;
import java.util.ArrayList;
public class Spacer {
public static void main (String args[]) {
System.out.println("QQ,2 = " + spacey("QQ", 2) + ", expected 4");
System.out.println("ABCA,2 = " + spacey("ABCA",2) + ", expected 4");
System.out.println("DEDEE,1 = " + spacey("DEDEE", 1) + ", expected 6");
System.out.println("JKJK,2 = " + spacey("JKJK", 2) + ", expected 5");
}
private static int spacey(String word, int spaces) {
// int shift = 0;
HashMap<Character, Integer> hm = new HashMap<>();
for (int i=0; i<word.length(); i++) {
char letter = word.charAt(i);
System.out.println(i + "=" + letter + " last saw " + hm.get(word.charAt(i)));
if (hm.get(letter) == null) {
hm.put(letter, i);
} else {
System.out.println(i + "-" + hm.get(letter) + "<=" + spaces);
if (i - hm.get(word.charAt(i)) <= spaces) {
// System.out.println("add " + (spaces + 1 - (i - hm.get(letter))));
// shift += (spaces + 1) - (i - hm.get(letter));
word = word.substring(0, i) + "_" + word.substring(i);
System.out.println(i + " word=" + word);
}
hm.put(letter, i); // update the hashmap with the last seen again
}
}
return word.length();
}
}
Your question is (mainly) about inserting underscores. A key insight that can help move forward is that the input and output strings are different, so it would be cleaner to treat them as such, using a StringBuilder for example. Additionally, it doesn't hurt at this stage to use temporary variables to capture concepts such as distance between characters. Leveraging these two ideas, you can have more self-explanatory code, for example:
public static String space(String input, int spaces) {
HashMap<Character, Integer> map = new HashMap<>();
StringBuilder result = new StringBuilder();
for( char symbol : input.toCharArray() ) {
int position = result.length();
int lastPosition = map.getOrDefault(symbol, position-spaces-1);
int distance = position - lastPosition -1;
for( int j = 0; j < Math.max( spaces - distance, 0) ; j++ ) {
result.append('_');
}
result.append(symbol);
map.put(symbol, result.length()-1);
}
return result.toString();
}
(and once this is mastered and digested, it's of course possible to in-line the temps)
The requirement doesn't ask you to display the constructed string so we need to only do calculations. The regex (.+)\1 will match any repetition of 1 or more chars and countPattern returns how many times that pattern was found.
public static void main(String[] args) {
System.out.println("QQ,2 = " + spacey("QQ", 2) + ", expected 4");
System.out.println("ABCA,2 = " + spacey("ABCA",2) + ", expected 4");
System.out.println("DEDEE,1 = " + spacey("DEDEE", 1) + ", expected 6");
System.out.println("JKJK,2 = " + spacey("JKJK", 2) + ", expected 6"); //in becomes JK__JK, ie. 4 + 2x'_'
}
private static int spacey(String word, int spaces) {
if(spaces<0){
throw new IllegalArgumentException("should be positive value");
}
if(word==null){
return 0;
}
if(spaces==0){
return word.length();
}
final Pattern repeatedCharRegex = Pattern.compile("(.+)\\1");
final int repetitions = countPattern(word, repeatedCharRegex);
return word.length() + repetitions*spaces;
}
public static int countPattern(String references, Pattern referencePattern) {
Matcher matcher = referencePattern.matcher(references);
int count = 0;
while (matcher.find()){
count++;
}
return count;
}
First of all you have an error in one of your test cases. Assuming you want to reproduce the cases in the quoted challenge, you need a 1 as second argument to the call to spacey here:
System.out.println("DEDEE,1 = " + spacey("DEDEE", 1) + ", expected 6");
// ^ ^
The formula to calculate the number of underscores to insert is:
previousindex + n + 1 - i
...where previousindex is the index at which the current letter occurred before, and i is the current index.
You can repeat an underscore with the .repeat string method. Don't forget to update i afterwards, so it keeps pointing to the currently processed character (which moved forward).
So your code could work like this:
import java.lang.Math;
import java.util.HashMap;
import java.util.ArrayList;
public class Spacer {
public static void main (String args[]) {
System.out.println("QQ,2 = " + spacey("QQ", 2) + ", expected 4");
System.out.println("ABCA,2 = " + spacey("ABCA",2) + ", expected 4");
System.out.println("DEDEE,1 = " + spacey("DEDEE", 1) + ", expected 6");
System.out.println("JKJK,2 = " + spacey("JKJK", 2) + ", expected 5");
}
private static int spacey(String word, int spaces) {
HashMap<Character, Integer> hm = new HashMap<>();
for (int i=0; i<word.length(); i++) {
char letter = word.charAt(i);
if (hm.get(letter) == null) {
hm.put(letter, i);
} else {
int underscores = hm.get(letter) + spaces + 1 - i;
if (underscores > 0) { // Need to add underscores
word = word.substring(0, i) + "_".repeat(underscores) + word.substring(i);
i += underscores; // update i so it still points to the current character
}
hm.put(letter, i);
}
}
return word.length();
}
}
if (posOfGuessLetter == -1)
{
System.out.print("Your letter was not found in the
spaces provided");
} //if
if (posOfGuessLetter == 0)
{
displayWordAsDashes = (guessLetter +
displayWordAsDashes.substring(posOfGuessLetter + 1));
displayWord =
displayWordAsDashes.substring(posOfGuessLetter + 1);
} //if
if (posOfGuessLetter == 9)
{
displayWordAsDashes = (displayWordAsDashes.substring(0,
posOfGuessLetter) + guessLetter);
displayWord = (displayWordAsDashes.substring(0,
posOfGuessLetter));
} //if
else
{
displayWordAsDashes = (displayWordAsDashes.substring(0,
posOfGuessLetter) + guessLetter +
displayWordAsDashes.substring(posOfGuessLetter + 1));
displayWord = (displayWordAsDashes.substring(0,
posOfGuessLetter) +
(displayWordAsDashes.substring(posOfGuessLetter + 1)));
}
while (displayWord.contains(guessLetter))
{
displayWordAsDashes = (displayWordAsDashes.substring(0,
posOfGuessLetter) + guessLetter +
displayWordAsDashes.substring(posOfGuessLetter + 1));
displayWord = (displayWordAsDashes.substring(0,
posOfGuessLetter) +
(displayWordAsDashes.substring(posOfGuessLetter + 1)));
} //while
} //else
System.out.print("The updated word is: " +
displayWordAsDashes);
I am trying to create a hangman program, and in this part it checks the index position of a user input for the character they want to find in the word and then removes the dash on that index and reveals the letter they just guessed. However, my program is not revealing both letters if the word has two of the same letter (i.e. naRRowing, lOOps) which is what I tried to program the while loop at the end to do. Can anyone tell me what I messed up on??
I didn't see what error you did but both pos == 0 and pos == 9 are superfluous due to
aString.substring(aString.length());
and
aString.substring(0, 0);
both returning the empty string.
If you don't have to keep track of where the letter was you could do something like this:
private String wordToGuess = "hangman";
private String guessedSoFar = wordToGuess.replaceAll(".", "-");
private String leftToGuess = wordToGuess;
public String guess(char c) {
for(int i = 0 ; i < leftToGuess.length() ; i++) {
if(leftToGuess.charAt(i) == c) {
guessedSoFar = guessedSoFar.substring(0, i) + c + guessedSoFar.substring(i + 1);
}
}
leftToGuess = leftToGuess.replace(c, '-');
return guessedSoFar;
}
I am very new to learning Java and currently I am working on a program that lets me fight the computer based on simple stats that I have assigned us and a random number to function as a dice roll. I recognize that there may be numerous other problems with my code, but the main issue I am trying to resolve is the "Syntax error on tokens, delete these tokens" on line 84 and the "Syntax error, insert "}" to complete Statement" on line 77.
I don't see what the issue is. What am I doing wrong? Both issues are listed near the bottom of my code in comments next to their corresponding lines.
import java.util.Scanner;
import java.util.Random;
public class Fight {
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
System.out.println("Enter your name");
String you = keyboard.next();
int youWounds = 1;
int youTough = 4;
int youAttack = 1;
int youWS = 4;
int youAS = 3;
String Comp = "Bad Guy";
int compWounds = 1;
int compTough = 4;
int compAttack = 1;
int compWS = 4;
int compAS = 3;
System.out.println(you + ", do you want to FIGHT?!?!?");
System.out.println("Yes / No?");
String inputString = keyboard.next();
if (inputString.equalsIgnoreCase("Yes")) {
System.out.println("FIGHT!!!!");
while (youWounds > 0 && compWounds > 0) {
int youRan = new Random().nextInt(6)+1; // this is where you roll to hit
System.out.println(you + " rolls " + youRan +" to hit");
if (youRan >= 7-youWS) { // this is the logic for roll to hit
System.out.println(you +" hit");
int youRanTW = new Random().nextInt(6)+1; // this is where you check to see if your hit wounds
System.out.println(you + " rolls " + youRanTW +" to wound");
if (youRanTW > compTough) { // this is the logic for roll to wound
System.out.println(you+" wounds"+Comp);
compWounds = compWounds - 1; // this is where comp loses a wound
if (compWounds <= 0) { // this is the logic for wound loss
System.out.println(Comp+" dies!!!");
} else {
System.out.println("But, "+Comp+" fights on!");
}
} else {
System.out.println(you=" does not wound");
}
} else {
System.out.println(you +" misses");
}
int compRan = new Random().nextInt(6)+1;
System.out.println(Comp+" rolls " + compRan + " to hit");
if (compRan >= 7-compWS) { // this is the logic for roll to hit
System.out.println(Comp +" hit");
int compRanTW = new Random().nextInt(6)+1; // this is where you check to see if your hit wounds
System.out.println(Comp + " rolls " + compRanTW +" to wound");
if (compRanTW > youTough) { // this is the logic for roll to wound
System.out.println(Comp+" wounds"+you);
youWounds = youWounds - 1; // this is where you loses a wound
if (youWounds <= 0) { // this is the logic for wound loss
System.out.println(you+" dies!!!");
} else {
System.out.println("But, "+you+" fights on!");
}
} else {
System.out.println(Comp=" does not wound");
}
} else {
System.out.println(Comp +" misses");
}
} else { // this is wher I get "Syntax error, insert "}" to complete Statement". The "}" is underlined in red on my screen
if (youWounds <=0){
System.out.println(Comp+" WINS!!!!");
} else {
System.out.println(you+" WINS!!!!");
}
}
} else { // this is where i get "Syntax error on tokens, delete these tokens". it wants me to delete "} else".
System.out.println(you + " you are a looser!!!!!!!!");
}
keyboard.close();
}
}
There are a few issues with the flow of your program, but the current problem is that you are trying to use else on your while loop. This is not possible or necessary.
The while loop will continue until the defined condition is met. Once that happens, the while loop ends and the next line of code is executed.
So, remove the else { from the closing of the while loop. You can then just evaluate the results.
Here's the corrected code, with a couple comments to show WHERE to remove things:
import java.util.Random;
import java.util.Scanner;
public class Fight {
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
System.out.println("Enter your name");
String you = keyboard.next();
int youWounds = 1;
int youTough = 4;
int youAttack = 1;
int youWS = 4;
int youAS = 3;
String Comp = "Bad Guy";
int compWounds = 1;
int compTough = 4;
int compAttack = 1;
int compWS = 4;
int compAS = 3;
System.out.println(you + ", do you want to FIGHT?!?!?");
System.out.println("Yes / No?");
String inputString = keyboard.next();
if (inputString.equalsIgnoreCase("Yes")) {
System.out.println("FIGHT!!!!");
while (youWounds > 0 && compWounds > 0) {
int youRan = new Random().nextInt(6) + 1; // this is where you roll to hit
System.out.println(you + " rolls " + youRan + " to hit");
if (youRan >= 7 - youWS) { // this is the logic for roll to hit
System.out.println(you + " hit");
int youRanTW = new Random().nextInt(6) + 1; // this is where you check to see if your hit wounds
System.out.println(you + " rolls " + youRanTW + " to wound");
if (youRanTW > compTough) { // this is the logic for roll to wound
System.out.println(you + " wounds" + Comp);
compWounds = compWounds - 1; // this is where comp loses a wound
if (compWounds <= 0) { // this is the logic for wound loss
System.out.println(Comp + " dies!!!");
} else {
System.out.println("But, " + Comp + " fights on!");
}
} else {
System.out.println(you = " does not wound");
}
} else {
System.out.println(you + " misses");
}
int compRan = new Random().nextInt(6) + 1;
System.out.println(Comp + " rolls " + compRan + " to hit");
if (compRan >= 7 - compWS) { // this is the logic for roll to hit
System.out.println(Comp + " hit");
int compRanTW = new Random().nextInt(6) + 1; // this is where you check to see if your hit wounds
System.out.println(Comp + " rolls " + compRanTW + " to wound");
if (compRanTW > youTough) { // this is the logic for roll to wound
System.out.println(Comp + " wounds" + you);
youWounds = youWounds - 1; // this is where you loses a wound
if (youWounds <= 0) { // this is the logic for wound loss
System.out.println(you + " dies!!!");
} else {
System.out.println("But, " + you + " fights on!");
}
} else {
System.out.println(Comp = " does not wound");
}
} else {
System.out.println(Comp + " misses");
}
} // REMOVE THE ELSE AND BRACKET
if (youWounds <= 0) {
System.out.println(Comp + " WINS!!!!");
} else {
System.out.println(you + " WINS!!!!");
}
// REMOVE THIS BRACKET
} else { // this is where i get "Syntax error on tokens, delete these tokens". it wants me to delete "} else".
System.out.println(you + " you are a looser!!!!!!!!");
}
keyboard.close();
}
}
How do I not store values from the program when it loops back again. For example, if I plan to enter two families, first I will ask for the details of the first family and display their names, and then I want to use the same variables to collect the next family and display their names without having stored information from the previous family.
public static void main(String[] args) {
// TODO code application logic here
String ans;
String res;
double cont;
int cot;
String name;
String order = "";
do {
ans = JOptionPane.showInputDialog(null,"What is the name of the "
+ "family?" );
res = JOptionPane.showInputDialog(null, "How many member in the " + ans +
" family?");
cot = Integer.parseInt(res); // Converts res String to a number
for (int count = 1; count < cot; count ++) {
name = JOptionPane.showInputDialog(null, " Enter first name: " + count);
order += name + " " + ans + "\n";
}
JOptionPane.showMessageDialog(null, "Members of the " + ans
+ " Family" + "\n" + order);
cont = JOptionPane.showConfirmDialog(null, "Do you want to add another "
+ "family", "Membership", JOptionPane.YES_NO_OPTION);
}while (cont == JOptionPane.YES_OPTION);
if (cont == JOptionPane.NO_OPTION){
JOptionPane.showMessageDialog(null," Come Back Again");
}
}
}
Your order variable is a String that you are adding the names to. Just reset it at the beginning of the loop:
...
do {
order = "";
...
I am having an incredibly difficult time trying to figure out why I am getting this error.
When I use a driver file to test the program it fails horribly.
Here's my code:
import java.util.Scanner;
import java.lang.Math.*;
public class Histogram
{
private int[] arrayData;
private int[] arrayRange;
private final int LOW = 1;
private final int HIGH = 100;
public Histogram()
{
int[] arrayData = new int[11];
}
public void getInput()
{
int[] arrayRange = new int[11];
for(int count = 1; count < arrayRange.length; count++)
{
arrayRange[count] = count * 10;
}
Scanner input = new Scanner(System.in);
System.out.println("Enter numbers from 1 to 100, Type -999 to quit.");
int nextNumb = input.nextInt();
while(nextNumb != -999)
{
if(nextNumb >= LOW && nextNumb <= HIGH)
{
for(int i = 0; i <= arrayRange.length; i++)
{
if(nextNumb > arrayRange[i] && nextNumb <= arrayRange[i+1])
arrayData[i]++;
}
nextNumb = input.nextInt();
}
else arrayData[10]++;
nextNumb = input.nextInt();
}
}
public String starPrint(double count)
{
String star = "";
count = (Math.round(count) / 5);
for(int i = 1; i <= count; i++)
{
star = star + "*";
}
return star;
}
public String toString()
{
String results = " Range | Histogram" + "\n";
results = results + "1 - 10 | " + starPrint(arrayData[0]) + "\n";
results = results + "11 - 20 | " + starPrint(arrayData[1]) + "\n";
results = results + "21 - 30 | " + starPrint(arrayData[2]) + "\n";
results = results + "31 - 40 | " + starPrint(arrayData[3]) + "\n";
results = results + "41 - 50 | " + starPrint(arrayData[4]) + "\n";
results = results + "51 - 60 | " + starPrint(arrayData[5]) + "\n";
results = results + "61 - 70 | " + starPrint(arrayData[6]) + "\n";
results = results + "71 - 80 | " + starPrint(arrayData[7]) + "\n";
results = results + "81 - 90 | " + starPrint(arrayData[8]) + "\n";
results = results + "91 - 100 | " + starPrint(arrayData[9]) + "\n";
results = results + "Outliers: " + starPrint(arrayData[10]) + "\n";
return results;
}
}
I believe that the problem is in my getInput method
right here to be precise:
if(nextNumb > arrayRange[i] && nextNumb <= arrayRange[i+1])
arrayData[i]++;
I have no idea what's wrong with it though I am a beginner programmer and couldn't find a solution to this particular problem.
Thanks for any help you're able to give!
public Histogram()
{
int[] arrayData = new int[11];
}
You're shadowing your arrayData field in the constructor. This is creating a local variable with the same name as your class's arrayData field, initializing it, then immediately discarding it. When you try to use the field later in your code, it's null. Get rid of the int[] part.
Note that your next exception will be an ArrayIndexOutOfBoundsException ... you should look at your loop ;)
this: for(int i = 0; i <= arrayRange.length; i++)
wont work since you are trying to access arrayRange[i] and arrayRange[i+1]
which dont exists for i = arrayRange.length-1 and further
so change it to:
for(int i = 0; i < arrayRange.length-1; i++)