I wish to put the raw questions(rawQuestions) as inputted in this way in command prompt:
java Hangman Hello test 123, into the array (questions). I know rawQuestion will not work down in the "store valid questions into an array" part because of
"error: ';' expected " and "error: not a statement"
in the line
" questions[vCount] = String rawQuestion; "
Therefore how should I rewrite it?
public class Hangman {
//Validation of raw questions
public static boolean isValidQuestion(String rawQuestion){
rawQuestion = rawQuestion.toUpperCase();
boolean vQuestion = true;
for(int i=0; i<rawQuestion.length(); i++){
char c = rawQuestion.charAt(i);
if(!(c>='A' && c<='Z'))
vQuestion = false;
}
return vQuestion;
}
public static void main(String args[]){
boolean vQs[] = new boolean[args.length];
for(int i=0; i<args.length; i++){
String rawQuestion = args[i];
boolean b = isValidQuestion(rawQuestion);
if(b)
System.out.println(rawQuestion + " is a valid question!");
else
System.out.println("Error: " + rawQuestion + ", input must be a word consist of a-z or A-Z");
vQs[i] = b;
}
//count the number of valid questions
int vCount = 0;
for(int i=0; i<vQs.length; i++){
System.out.println(i + " " + vQs[i] );
if(vQs[i])
vCount++;
}
System.out.println("There are " + vCount + " valid questions");
//store valid questions into an array
String questions[] = new String[vCount];
for(vCount=0; vCount<args.length; vCount++){
questions[vCount] = String rawQuestion;
System.out.println( questions[vCount] );
}
}
}
Try this:
String[] validQuestions = Arrays.stream(args)
.filter(Hangman::isValidQuestion)
.toArray(String[]::new);
int validQuestionCount = validQuestions.length;
But even without Streams, your whole method could be done in one for loop, counting and collecting the valid questions in one go instead of having three separate steps:
List<String> validQuestions = new ArrayList<>();
for (int i = 0; i < args.length; i++)
{
String rawQuestion = args[i];
boolean b = isValidQuestion(rawQuestion);
if (b)
{
validQuestions.add(rawQuestion);
System.out.println(rawQuestion + " is a valid question!");
}
else
{
System.out.println("Error: " + rawQuestion + ", input must be a word consist of a-z or A-Z");
}
}
// count the number of valid questions
System.out.println("There are " + validQuestions.size() + " valid questions");
// store valid questions into an array
String questions[] = validQuestions.toArray(new String[validQuestions.size()]);
This way, you do not have to juggle the index variables yourself, which is hard to understand, especially if somebody else tries to read it. (Especially the re-use of vCount is kinda scary to me)
I fixed something and commented, not sure if it works, i haven't compiled it.
public static void main(String args[]){
boolean vQs[] = new boolean[args.length];
int vCount=0;
for(int i=0; i<args.length; i++){
String rawQuestion = args[i];
if(isValidQuestion(rawQuestion)){
System.out.println(rawQuestion + " is a valid question!");
//Here you have enough data to count the valid questions, three loops are not needed.
++vCount;
vQs[i]=true;
}else{
System.out.println("Error: " + rawQuestion + ", input must be a word consist of a-z or A-Z");
vQs[i]=false;
}
}
System.out.println("There are " + vCount + " valid questions");
//store valid questions into an array
String questions[] = new String[vCount];
int j=0;
for(int i=0; i<args.length; i++){
//You need to iterate for all strings, because vQs[] is long args.length
if(vQs[i]){
//Ok the i-th question was valid, let's move it and print it
questions[j] = args[i];
System.out.println( questions[j] );
++j;
}
}
}
}
Related
I'm writing a simple vowel-counter and was wondering if there's a cleaner alternative (possibly a loop?) to replace all of the else if's when comparing s to the various vowels.
I can't think of a simple way to do this effectively as the number of each vowel must be shown individually. It would be very simple if it was just a total vowel count.
I'm quite new to Java so I don't know what can be used to clean this up. If this is the best option, then I am contempt -- but I love cleaning up code where it can be!
import java.util.Scanner;
class Main {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int A = 0, E = 0, I = 0, O = 0, U = 0;
System.out.print("Type a single word > ");
String word = input.next();
for (int i = 0; i < word.length(); i++) {
String s = word.substring(i, i + 1);
if (s.equalsIgnoreCase("A")) { A++; }
else if (s.equalsIgnoreCase("E")) { E++; }
else if (s.equalsIgnoreCase("I")) { I++; }
else if (s.equalsIgnoreCase("O")) { O++; }
else if (s.equalsIgnoreCase("U")) { U++; }
}
int total = A + E + I + O + U;
System.out.println("\n'" + word + "' has...\n" + A + " A's\n" + E + " E's\n" + I + " I's\n" + O + " O's\n" + U + " U's\nTotal vowels: " + total + "\n");
input.close();
}
}
Input:
Coding
Output:
'Coding' has...
0 A's
0 E's
1 I's
1 O's
0 U's
Total vowels: 2
Here is a less repetitive way to code it, using an int array for the counts, and a string holding the sequence of vowels.
import java.util.Scanner;
class Main {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Type a single word > ");
String word = input.next();
String vowels = "AEIOU";
int[] counts = new int[vowels.length()];
int total = 0;
for (int i = 0; i < word.length(); i++) {
int index = vowels.indexOf(Character.toUpperCase(word.charAt(i)));
if (index >= 0) {
++counts[index];
++total;
}
}
System.out.printf("%n'%s' has...%n", word);
for (int i = 0; i < counts.length; ++i) {
System.out.printf("%s %s's%n", counts[i], vowels.charAt(i));
}
System.out.printf("Total vowels: %s%n", total);
}
}
Output:
Type a single word > Coding
'Coding' has...
0 A's
0 E's
1 I's
1 O's
0 U's
Total vowels: 2
You could avoid a lot of repetition by using a Map that associates vowels (keys) to their frequencies within the word passed at runtime (values).
It is worth noting that a LinkedHashMap is used in the below example as to preserve the insertion order of keys for printing at the end of the program - as would not be the case with a HashMap.
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
// Define Map to map vowels to frequencies
Map<Character, Integer> vowels = new LinkedHashMap<Character, Integer>();
vowels.put('A', 0);
vowels.put('E', 0);
vowels.put('I', 0);
vowels.put('O', 0);
vowels.put('U', 0);
// Get input from user
System.out.print("Type a single word > ");
String word = input.next();
// Iterate across word
for (int i = 0; i < word.length(); i++) {
String c = word.substring(i, i+1); // Get current char
for (Character key : vowels.keySet()) { // Iterate across vowels
if (c.equalsIgnoreCase(key.toString())) {
vowels.put(key, vowels.get(key)+1); // Increment vowel frequency if matched
break; // Break inner loop and move to next char in word
}
}
// Sum total
int total = 0;
for (Character key : vowels.keySet()) {
total += vowels.get(key);
}
// Print results to console
System.out.println("\'" + word + "\'" + " has...");
for (Character key : vowels.keySet()) {
System.out.println(vowels.get(key) + " " + key + "\'s");
}
System.out.println("Total vowels: " + total);
input.close();
}
}
}
I'm currently working on a version of hangman through java. I've recently been stumped by a problem that I can't seem to solve.
I have an array easyDifficulty and a String hiddenWord. I want to make it so that every time the game starts, my method randomWord() will choose a random word from array easyDifficulty to start the program. Many of my methods use hiddenWord so I pasted all of my code below incase you need to check that. Otherwise, the main parts that I feel like that are causing problems are in the area where I declare my field variables, my randomWord method, and the main method.
import java.util.Arrays;
import java.util.*;
import java.util.Scanner;
public class HangmanGame {
static String[] easyDifficulty = new String[]{"orange", "jacket","shirt"
,"rocket","airplane","circle","balloon","swing","truck","caterpillar"};
static Random rand = new Random();
static String hiddenWord = new String("");
static char[] hiddenWordToChar = hiddenWord.toCharArray();
static int triesLeft = 6;
static boolean done = false;
static int length = hiddenWord.length();
static Scanner input = new Scanner(System.in);
final static int maxLength = 30;
static char[] repeatChecker = new char[30]; //this is to help prevent the user from putting the same char multiple times
static char[] fillWord = new char[length];
static int var;
static int var2;
static char underscore = '_';
static int chooseDifficultyInt;
public static String randomWord(int n) {
int randomNum = rand.nextInt(9);
int difficultyInt = n;
if (difficultyInt == 1){
//System.out.println(easyDifficulty[randomNum]);
return easyDifficulty[randomNum];
}
return null;
}
public static boolean contains(char[] arr, char i) {
for (char n : arr) {
if (i == n) {
return true;
}
}
return false;
}
public static boolean multiLetter(char[] arr, char i){
int multiple = 0;
for (char n : arr){
if (i == n){
multiple++;
//continue;
}
}
System.out.println(multiple);
if (multiple > 1){
return true;
}
else {
return false;
}
}
public static void createSpaces(int n){
for (int i = 0; i <= n-1; i++){
fillWord[i] = underscore;
}
System.out.println(fillWord);
}
public static void tryAgain(){
System.out.println("Would you like to try again? Enter Y/N to go again or quit!");
char goAgain = input.next().charAt(0);
goAgain = Character.toLowerCase(goAgain);
if (goAgain == 'y') {
triesLeft = 6;
repeatChecker = new char[20];
main(null);
}
else if (goAgain == 'n') {
System.out.println("Bye!");
System.exit(0);
}
else {
System.out.println("Invalid input");
tryAgain();
}
}
public static void arrayLetters(){
System.out.println("This is a " + length + " letter word. Please enter a letter to guess: ");
char charInput = input.next().charAt(0);
char[] letters = new char[20];
//This code only runs if the user inputs a letter that repeats
//throughout hiddenWord
if (multiLetter(hiddenWordToChar, charInput)){
for (int n = 0; n < length; n++){
char multiWordLetter = hiddenWord.charAt(n);
letters[n] = multiWordLetter;
if (letters[n] == charInput){
fillWord[n] = charInput;
}
if (contains(repeatChecker, charInput)){
System.out.println("You already did that word, try again!");
arrayLetters();
}
if (Arrays.equals(fillWord, hiddenWordToChar)){
System.out.println("Congratulations, you win! The word was '" + hiddenWord + "'!");
System.out.println("You completed the challenge in " + triesLeft + " tries! \n\n");
tryAgain();
}
}
System.out.println(fillWord);
System.out.println("Nice! There is a(n) " + charInput + " in this word!");
System.out.println("You have " + triesLeft + " tries left!\n");
arrayLetters();
}
//This block of code runs when the user input a letter that only occurs once
//in hiddenWord
for (int i = 0; i < length; i++){
char wordLetter = hiddenWord.charAt(i);
letters[i] = wordLetter;
if (contains(letters, charInput)){
/*
if (multiLetter(letters, charInput)){
System.out.println("aylmao");
}
*/
//System.out.println(multiLetter(hiddenWordArray, charInput));
if (contains(repeatChecker, charInput)){
System.out.println("You already did that word, try again!");
arrayLetters();
}
repeatChecker[var] = charInput;
var++;
fillWord[i] = charInput;
if (Arrays.equals(fillWord, hiddenWordToChar)){
System.out.println("Congratulations, you win! The word was '" + hiddenWord + "'!");
System.out.println("You completed the challenge in " + triesLeft + " tries! \n\n");
tryAgain();
}
System.out.println(fillWord);
System.out.println("Nice! There is a(n) " + charInput + " in this word!");
System.out.println("You have " + triesLeft + " tries left!\n");
arrayLetters();
}
if (i == length-1){
System.out.println("There is no " + charInput + " in this word!");
triesLeft--;
System.out.println("You have " + triesLeft + " tries left!\n");
if (triesLeft <= 0){
System.out.println("You failed!\n\n");
tryAgain();
}
arrayLetters();
}
}
}
public static void main(String[] args) {
System.out.println("Welcome to my hangman game!");
System.out.println("Please input your prefered difficulty level.");
System.out.println("1. Easy");
System.out.println("2. Medium");
System.out.println("3. Hard");
chooseDifficultyInt = input.nextInt();
randomWord(chooseDifficultyInt);
hiddenWord = randomWord(chooseDifficultyInt);
createSpaces(length);
arrayLetters();
}
}
I'm an intermediate in java programming so I've learned that Strings are immutable. Thus I've considered that the reason why hiddenWord won't be set equal to randomWord(chooseDifficultyInt); is because of that?
I'm an intermediate in java programming so I've learned that Strings are immutable
This often causes confusion among new programmers. This is correct, Strings are immutable. However the variable that points to that String can be re-assigned (assuming it isn't final).
You can modify your hidden word as many times as you like:
HangmanGame.hiddenWord = "MyNewWord";
HangmanGame.hiddenWord = "AnotherWord";
HangmanGame.hiddenWord = "ThisWorks";
You might be wondering how the hiddenWord is changing if Strings are immutable.
Your variable isn't actually changing. Every time you re-assign it, a new String is being created. This means that the Strings themselves are never modified.
So yes, you can call
HangmanGame.hiddenWord = HangmanGame.randomWord(n);
and it will work perfectly.
Your initialization of hiddenWord as new String(""); is useless. You could remove it safely.
When you do that:
hiddenWord = randomWord(chooseDifficultyInt);
you set hiddenWord to the reference of a random string of your predefined list, not allocating anything, just reusing an existing string reference.
I'm trying to create a program that takes each number typed in by the user and sort them out as even, odd and the number zero values.
The result should look like something like this:
User Input: 14005
Output:
Even Numbers: 4
Odd Numbers: 1, 5
Zero's: 0, 0
This is the code I've written, I thought of using string concatination in order to add a new value each time the loop checks for the next character, don't know whether I'm thinking right or not though, would appriciate if someone could tell me where I'm thinking in the wrong way.
package com.craydesign;
import javax.swing.JOptionPane;
public class Main {
public static void main(String[] args) {
String number = JOptionPane.showInputDialog("Please enter a number: ");
String evenNumbers = "";
String oddNumbers = "";
String numberZero = "";
for(int i = 0; i < number.length(); i++) {
if(number.charAt(i) % 2 == 0) {
evenNumbers.concat(Integer.toString(i) + ", ");
} else if(number.charAt(i) % 2 != 0) {
oddNumbers.concat(Integer.toString(i) + ", ");
} else if (number.charAt(i) == 0){
numberZero.concat(Integer.toString(i) + ", ");
}
}
JOptionPane.showMessageDialog(null, "Even numbers: " + evenNumbers + "\n" + "Odd numbers: " + oddNumbers + "\n" + "Zero's: " + numberZero);
}
}
use Character.getNumericValue() instead of charAt(i)
public static void main(String[] args) throws IOException
{
String number = JOptionPane.showInputDialog("Please enter a number: ");
StringBuffer evenNumbers = new StringBuffer();
StringBuffer oddNumbers =new StringBuffer();
StringBuffer numberZero =new StringBuffer();
for(int i = 0; i < number.length(); i++) {
int value=Character.getNumericValue(number.charAt(i));
if(value!=0 && value % 2 == 0) {
evenNumbers.append(value).append(',');
} else if(value % 2 != 0) {
oddNumbers.append(value).append(',');
} else if (value == 0){
numberZero.append(value).append(',');
}
}
JOptionPane.showMessageDialog(null, "Even numbers: " + evenNumbers + "\n" + "Odd numbers: " + oddNumbers + "\n" + "Zero's: " + numberZero);
}
EDIT:(displaying numbers in sorted order)
String evenNo[]=evenNumbers.toString().split(",");
String oddNo[]=oddNumbers.toString().split(",");
Arrays.sort(evenNo);
Arrays.sort(oddNo);
JOptionPane.showMessageDialog(null, "Even numbers: " + Arrays.toString(evenNo) + "\n" + "Odd numbers: " + Arrays.toString(oddNo) + "\n" + "Zero's: " + Arrays.toString(numberZero.toString().substring(0,
numberZero.length()-1).split(",")));
You are using String for output and appending the output in the string.
Its a bad idea. as String class is immutable so if you do change anything in String it will create a new Object in memory.
So your solution will take extra memory.
Accroding to me you can solve this problem in two ways
Use StringBuffer class instead of String class for appending
Use ArrayList to Store your result. and iterate over the arraylist and show the output as you want.
Thanks,
Aman
What I have is a program that will read a text file that has data from a file that is in the format
`FootballTeamName1 : FootballTeamName2 : FootballTeam1Score : FootballTeam2Score
Currently it reads in the file and will split it at each colon what I want to know is how would I make it so that each time it comes across a name then it will add that name to the list if it doesn't already exist or if it does then it will not create a duplicate value rather it will add the values to the values that already exist for that teams name.
I currently have a program that can get the values for when you search for a team but what I want to do is make it so that it is possible when the user does not specify a team then it will make it so that it will return the results for all of the teams. Here is what I have currently which asks for the location of the file and asks the user for specifying a file which works but I'm not sure how to do what I want.
import java.awt.Desktop;
import java.io.*;
import java.util.*;
public class reader {
//used to count the number of invalid and valid matches
public static boolean verifyFormat(String[] words) {
boolean valid = true;
if (words.length != 4) {
valid = false;
} else if (words[0].isEmpty() || words[0].matches("\\s+")) {
valid = false;
} else if ( words[1].isEmpty() || words[1].matches("\\s+")) {
valid = false;
}
return valid && isInteger(words[2]) && isInteger(words[3]);}
//checks to see that the number of items in the file are equal to the four needed and the last 2 are integers
//also checks to make sure that there are no results that are just whitespace
public static boolean isInteger( String input ) {
try {
Integer.parseInt( input );
return true;
}
catch( Exception e ) {
return false;
}
}
//checks to make sure that the data is an integer
public static void main(String[] args) throws IOException {
Scanner sc = new Scanner(System.in);
while(true){ //Runs until it is specified to break
Scanner scanner = new Scanner(System.in);
System.out.println("Enter filename");
String UserFile = sc.nextLine();
File file = new File(UserFile);
if(!file.exists()) {
continue;
}
if(UserFile != null && !UserFile.isEmpty()){
System.out.println("Do you want to generate plain (T)ext or (H)TML");
String input = scanner.nextLine();
if ( input.equalsIgnoreCase("H") ) {
processFile(UserFile) ; }
else if ( input.equalsIgnoreCase("T")){
processFile(UserFile);
}
else{
System.out.println("Do you want to generate plain (T)ext or (H)TML");
}
}
}
}
//checks how the user wants the file to be displayed
private static void processFile(String UserFile) throws FileNotFoundException {
String hteam;
String ateam;
int hscore;
int ascore;
int totgoals = 0;
int gamesplayed = 0;
int gs = 0;
int gc = 0;
int w = 0;
int d = 0;
int l = 0;
String newLine = System.getProperty("line.separator");//This will retrieve line separator dependent on OS.
Scanner s = new Scanner(new BufferedReader(
new FileReader(UserFile))).useDelimiter("\\s*:\\s*|\\s*\\n\\s*");
Scanner scanner = new Scanner(System.in);
System.out.println("Enter the name of the team you want the results for");
String input = scanner.nextLine();
while (s.hasNext()) {
String line = s.nextLine();
String[] words = line.split("\\s*:\\s*");
//splits the file at colons
if(verifyFormat(words)) {
hteam = words[0]; // read the home team
ateam = words[1]; // read the away team
hscore = Integer.parseInt(words[2]); //read the home team score
totgoals = totgoals + hscore;
ascore = Integer.parseInt(words[3]); //read the away team score
totgoals = totgoals + ascore;
if ( input.equalsIgnoreCase(hteam)){
gamesplayed = gamesplayed + 1;
gs = gs + hscore;
gc = gc + ascore;
if (hscore > ascore)
w = w + 1;
else if (ascore > hscore)
l = l + 1;
else
d = d + 1;
}
else if (input.equalsIgnoreCase(ateam)){
gamesplayed = gamesplayed + 1;
gs = gs + ascore;
gc = gc + hscore;
if (hscore < ascore)
w = w + 1;
else if (ascore < hscore)
l = l + 1;
else
d = d + 1;
}
}
}
System.out.println(input + newLine + "--------------------------" + newLine + "Games played: " + gamesplayed + newLine + "Games Won: " + w + newLine + "Games Drawn: " + d + newLine + "Games Lost: " + l + newLine + "Goals For: " + gs + newLine + "Goals Against: " + gc);
}
}
If you want no duplicate elements in your collection use a Set. A Set is a collection that contains no duplicate elements (doc here).
Sounds like you want a Map from Team to Score, where if the team already exists, then get the value from the map, and and the score to that.
You can add the entries into a Set (or if you want them sorted - SortedSet). Since Set only holds unique values - you'll always have only one "copy" of each value.
For reference, the following code uses 5 values, but the set will have only 3 (unique) values:
String str = "A : B : C : B : A";
String[] vals = str.split(":");
SortedSet<String> myVals = new TreeSet<String>();
for(String val : vals)
{
myVals.add(val.trim());
}
System.out.println("Set size: " + myVals.size());
I have this assignment for tomorrow and I'm a beginner please help. Must be JOptionpane :O I was wondering if I can use if else statement in showmessagedialog. Error says incompatible types required: int ( for holder=holder + "\n" + aw[x];
Here's what I've done so far(SORRY I'M A BEGINNER PLS UNDERSTAND):
public static void main(String[] args) {
String s;
int size;
int size2;
int holder;
s = JOptionPane.showInputDialog("Enter the size of the array");
size = Integer.parseInt(s);
String aw[]= new String[size];
for (int x=0; x<=aw.length-1; x++){
aw[x]=JOptionPane.showInputDialog("Enter value for array[" + x + "]");
size2 = Integer.parseInt(aw[x]);
}
for (int x=0; x<=aw.length-1;x++)
{
holder=holder + "\n" + aw[x];
}
JOptionPane.showMessageDialog(null, if (holder<0) { holder + " is negative" } else holder " is positive");
}
}'
holder is declared as an int, but in
holder=holder + "\n" + aw[x];
you try to assign it a String.
Use String to store your messge
String msg;
if (holder<0)
{
msg = holder + " is negative";
}
else
{
msg = holder " is positive";
}
JOptionPane.showMessageDialog(null,msg);
showMessageDialog function expects the second parameter to be String
Something you can not do:
1 Variable holder you declare is int type. It can not be used to do `+`` operation.
2 Two for -loop is not neccessary.
3 You forget to check whether the number entered is zero, you just have positive and negative logic.
4 When trying to use + opeartion for strings. Please use append method of StringBuilder.
Here is the code made based on the above 3 items.
public static void main(String[] args) {
String s;
int size;
int size2;
int holder = 0;
s = JOptionPane.showInputDialog("Enter the size of the array");
size = Integer.parseInt(s);
String aw[] = new String[size];
StringBuilder sb = new StringBuilder();
for (int x = 0; x <= aw.length - 1; x++) {
aw[x] = JOptionPane.showInputDialog("Enter value for array[" + x
+ "]");
size2 = Integer.parseInt(aw[x]);
if(size2 ==0)
{
sb.append(aw[x]).append(" is zero").append('\n');
}else if(size2 >0)
{
sb.append(aw[x]).append(" is positive").append('\n');
}else
{
sb.append(aw[x]).append(" is negative").append('\n');
}
}
JOptionPane.showMessageDialog(null, sb.toString());
}
The best approach is:
final String msg = holder == 0 ? "is zero" : (holder > 0 ? "is positive" : "is negative");
JOptionPane.showMessageDialog(null,msg);