I am trying to create a program which will be able to search a user inputed string for a specific word, and count the number of times that word is repeated.
For example I want the program to function like this:
Please enter a string of your choice:
kelowna is a nice city, kelowna is my home.
Enter a word for which you would like to search for:
kelowna
The word Kelowna was found 2 times.
How would I go about doing this? My initial approach was to use loops, but that hasn't got me too far.
This is what I have so far:
import java.util.Scanner;
public class FinalPracc {
public static void main(String[] args) {
Scanner s1 = new Scanner(System.in);
System.out.println("please enter a string of you choice: ");
String a = s1.nextLine();
System.out.println("Please enter the word you would like to search for: ");
String b = s1.nextLine();
int aa = a.length();
int bb = b.length();
if (a.contains(b)) {
System.out.println("word found");
int c = a.indexOf(b);
int
if (
}
}
/* ADD YOUR CODE HERE */
}
One approach would be that if you find the word, modify the search string to remove everything before and including the word, then search again:
public static void main(String[] args) {
Scanner s1=new Scanner(System.in);
System.out.println("please enter a string of you choice: ");
String a=s1.nextLine();
System.out.println("Please enter the word you would like to search for: ");
String b=s1.nextLine();
int count = 0;
while(b.contains(a)) {
count++;
int pos = b.indexOf(a);
b = b.substring(pos + a.length());
}
if (count > 0){
System.out.println("word found " + count + " times");
} else {
System.out.println("word not found");
}
}
Edit: Alternatively, if you don't want to call substring in a loop, you could use the form of indexOf that takes a starting index for the search. In this case, your loop might look like:
int count = 0;
int searchIndex = 0;
while((searchIndex = b.indexOf(a, searchIndex)) > -1) {
count++;
searchIndex += a.length();
}
Maybe something like while(a.contains(b))
and set up a counter by one every time a word is found and cut everything until the last sign of the found word every loop round.
Related
New to java. I need to ask the user the number of strings (consisting only of upper and lowercase letters, spaces, and numbers) they want to input. These strings need to be stored in an array. Then I created a boolean method to be able to tell if those strings are palindromic (ignoring spaces and cases). If it is palindromic then I add to the result list to print later on. I am confused on how to ask the user to input that exact amount of strings and how to check each individual string. I must use StringBuilder. This is what I have so far (it's kind of a mess, sorry). I feel like I'm using the StringBuilder/array wrong, how can I fix this?
public class Palindromes {
public static void main(String[] args) {
int numOfStrings;
Scanner scan = new Scanner(System.in); // Creating Scanner object
System.out.print("Enter the number of strings: ");
numOfStrings = scan.nextInt();
System.out.print("Enter the strings: ");
StringBuilder paliString = new StringBuilder(numOfStrings);
for(int n=0; n < paliString; n++){
paliString[n] = scan.nextLine();
scan.nextLine();
String[] stringPali = new String[numOfStrings];
StringBuilder str = paliString;
if(isPali(userString)){
paliString = append.userString;
}
System.out.println("The palindromes are: " + userString ";");
}
static boolean isPali(String userString) {
int l = 0;
int h = userString.length() - 1;
// Lowercase string
userString = userString.toLowerCase();
// Compares character until they are equal
while (l <= h) {
char getAtl = userString.charAt(l);
char getAth = userString.charAt(h);
// If there is another symbol in left
// of sentence
if (!(getAtl >= 'a' && getAtl <= 'z'))
l++;
// If there is another symbol in right
// of sentence
else if (!(getAth >= 'a' && getAth <= 'z'))
h--;
// If characters are equal
else if (getAtl == getAth) {
l++;
h--;
}
// If characters are not equal then
// sentence is not palindrome
else
return false;
}
// Returns true if sentence is palindrome
return true;
}
}
SAMPLE RESULT:
Enter the number of strings: 8
Enter the strings:
Race Car
Mountain Dew
BATMAN
Taco Cat
Stressed Desserts
Is Mayonnaise an instrument
swap paws
A Toyotas a Toyota
The palindromes are: Race Car; Taco Cat; Stressed Desserts; swap paws; A Toyotas a Toyota
As I think the best way to answer this is to help you learn in small steps, I tried to stick with your initial idea on how to solve this and edited your main method with minimal changes.
This one does the trick.
public static void main(String[] args) {
int numOfStrings;
Scanner scan = new Scanner(System.in); // Creating Scanner object
System.out.print("Enter the number of strings: ");
numOfStrings = scan.nextInt();
scan.nextLine(); // you need this to catch the enter after the integer you entered
System.out.print("Enter the strings: ");
StringBuilder paliString = new StringBuilder();
for (int n = 0; n < numOfStrings; n++) {
String userString = scan.nextLine();
if (isPali(userString)) {
if (paliString.length() > 0) {
paliString.append("; ");
}
paliString.append(userString);
}
}
System.out.println("The palindromes are: " + paliString);
}
Key changes:
I added scan.nextLine(); right after reading the number of strings. This handles the newline you get when the user hits enter.
You don't need to initialize the StringBuilder with numOfStrings. This just preallocates the size of the StringBuilder in characters. Not the number of strings. Either way, it's not necessary. StringBuilder grows as needed.
I suggest you inspect what I did inside the for-loop. This was the biggest mess and changed significantly.
Last but not least: Writing the result needs to be outside of the for-loop, after all palindromes have been added to the StringBuilder.
Edit
Based on your comment, in this next iteration, I changed the usage of StringBuilder to the usage of an ArrayList. (Which is something completely different)
I am using it here because Lists in Java grow on demand. And since the number of palindromes is probably not equal to the number of input strings, this is the way to go. To really assign it to an array, one could always call String[] paliStringsArray = paliStrings.toArray(new String[]{}); but as ArrayLists already use an underlying array and are not necessary to to generate the output you want, I didn't put it into the new version.
Please compare the differences of this step to the previous version. I also added this String.join("; ", paliStrings) part, which creates the output you want.
public static void main(String[] args) {
int numOfStrings;
Scanner scan = new Scanner(System.in); // Creating Scanner object
System.out.print("Enter the number of strings: ");
numOfStrings = scan.nextInt();
scan.nextLine(); // you need this to catch the enter after the integer you entered
System.out.print("Enter the strings: ");
List<String> paliStrings = new ArrayList<>();
for (int n = 0; n < numOfStrings; n++) {
String userString = scan.nextLine();
if (isPali(userString)) {
paliStrings.add(userString);
}
}
System.out.println("The palindromes are: " + String.join("; ", paliStrings));
}
And now to the last step. Arvind Kumar Avinash actually solved a part that I also missed in the initial question. (I'll read more carefully in the future). He was validating the user input. So for the last iteration, I added his validation code in a modified way. I put it into a method as I think that makes things clearer and gets rid of the necessity of a the boolean valid variable.
public static void main(String[] args) {
int numOfStrings;
Scanner scan = new Scanner(System.in); // Creating Scanner object
System.out.print("Enter the number of strings: ");
numOfStrings = scan.nextInt();
scan.nextLine(); // you need this to catch the enter after the integer you entered
System.out.print("Enter the strings: ");
List<String> paliStrings = new ArrayList<>();
for (int n = 0; n < numOfStrings; n++) {
String userString = readNextLine(scan);
if (isPali(userString)) {
paliStrings.add(userString);
}
}
System.out.println("The palindromes are: " + String.join("; ", paliStrings));
}
static String readNextLine(Scanner scanner) {
while (true) {
String userString = scanner.nextLine();
if (userString.matches("[A-Za-z0-9 ]+")) {
return userString;
} else {
System.out.println("Error: invalid input.");
}
}
}
I need to ask the user the number of strings (consisting only of upper
and lowercase letters, spaces, and numbers) they want to input. These
strings need to be stored in an array.
I have done the above part of your question. I hope, this will give you direction to move forward.
import java.util.Scanner;
public class Main {
public static void main(String args[]) {
Scanner scan = new Scanner(System.in);
boolean valid = true;
int numOfStrings = 0;
do {
valid = true;
System.out.print("Enter the number of strings: ");
try {
numOfStrings = Integer.parseInt(scan.nextLine());
} catch (NumberFormatException e) {
System.out.println("Error: invalid input.");
valid = false;
}
} while (!valid);
String[] stringPali = new String[numOfStrings];
String input;
for (int i = 0; i < numOfStrings; i++) {
do {
valid = true;
System.out.print("Enter a string consisting of only letters and digits: ");
input = scan.nextLine();
if (!input.matches("[A-Za-z0-9 ]+")) {
System.out.println("Error: invalid input.");
valid = false;
}
} while (!valid);
stringPali[i] = input;
}
}
}
A sample run:
Enter the number of strings: a
Error: invalid input.
Enter the number of strings: 3
Enter a string consisting of only letters and digits: Arvind
Enter a string consisting of only letters and digits: Kumar Avinash
Enter a string consisting of only letters and digits: !#£$%^&*()_+
Error: invalid input.
Enter a string consisting of only letters and digits: Hello #
Error: invalid input.
Enter a string consisting of only letters and digits: Hello 123
Feel free to comment in case of any doubt/issue.
Wish you all the best!
[Update]
Based on your request, I have posted the following update which asks for the strings only once and then allows the user to enter all the strings one-by-one:
import java.util.Scanner;
public class Main {
public static void main(String args[]) {
Scanner scan = new Scanner(System.in);
boolean valid = true;
int numOfStrings = 0;
do {
valid = true;
System.out.print("Enter the number of strings: ");
try {
numOfStrings = Integer.parseInt(scan.nextLine());
} catch (NumberFormatException e) {
System.out.println("Error: invalid input.");
valid = false;
}
} while (!valid);
String[] stringPali = new String[numOfStrings];
String input;
System.out.println("Enter " + numOfStrings + " strings consisting of only letters and digits: ");
for (int i = 0; i < numOfStrings; i++) {
do {
valid = true;
input = scan.nextLine();
if (!input.matches("[A-Za-z0-9 ]+")) {
System.out.println("Error: invalid input.");
valid = false;
}
} while (!valid);
stringPali[i] = input;
}
}
}
A sample run:
Enter the number of strings: 3
Enter 3 strings consisting of only letters and digits:
Arvind
Kumar
He$ll0
Error: invalid input.
Avinash
Feel free to comment in case of any doubt.
I am new to programming and I decided to learn Java. I had just finished reading about one dimensional array and I am having trouble with searching.
The summary of this program I had made is to ask the user how many students will be enrolled in the class. The user then inputs the name of the students based on the length of the array. Then I want the to be able to have the user search for the students name. How can i accomplish this? What I want to accomplish is when the user inputs the first name it will return the list of full names that has the matching first name. I really struggling with this. Please don't give any advanced methods. I would like to stay in pace pace with my book.
I am using introduction to java programming comprehensive version 10th edition.
import java.util.Scanner;
public class classSystem {
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
System.out.println("Weclome instructure to your Class System!");
System.out.println("Follow each steps to turn in your work instructor.");
System.out.println("\n1.) Enroll Students:");
System.out.print("\nHow many students are enrolled? ");
int studentAmount = input.nextInt();
String[] enrolledStudents = getStudentAttendance(studentAmount);
System.out.println("Here is your attendance list:");
for (int count = 0; count < enrolledStudents.length; count++) {
System.out.print("\n\t" + (count + 1) + ".) " + enrolledStudents[count]);
}
System.out.print("\n\nWhat sudent do you want to search: ");
String studentSearch = input.nextLine();
System.out.println(getStudent(enrolledStudents, studentSearch));
}
public static String[] getStudentAttendance(int studentAmount)
{
Scanner input = new Scanner(System.in);
String[] enrolledStudents = new String[studentAmount];
System.out.println("Input the students names:");
for (int count = 0; count < enrolledStudents.length; count++)
{
System.out.print((count + 1) + ".) ");
enrolledStudents[count] = input.nextLine();
}
return enrolledStudents;
}
public static String getStudent(String[] enrolledStudents, String StudentSearch)
{
for (int count = 0; count < enrolledStudents.length; count++)
{
if(StudentSearch.equals(enrolledStudents[count]))
{
return getStudent;
}
}
}
}
I have updated your code. Please see the comments inline. Hope this helps.
import java.util.Scanner;
class classSystem {
static Scanner input; //created a static reference for Scanner
//as you will be using in both the methods
public static void main(String[] args) {
input = new Scanner(System.in); //creating the Scanner object.
System.out.println("Weclome instructure to your Class System!");
System.out.println("Follow each steps to turn in your work instructor.");
System.out.println("\n1.) Enroll Students:");
System.out.print("\nHow many students are enrolled? ");
int studentAmount = input.nextInt();
input.nextLine(); //added this to consume new-line leftover
String[] enrolledStudents = getStudentAttendance(studentAmount);
System.out.println("Here is your attendance list:");
for (int count = 0; count < enrolledStudents.length; count++) {
System.out.print("\n\t" + (count + 1) + ".) " + enrolledStudents[count]);
}
System.out.print("\n\nWhat sudent do you want to search: ");
String studentSearch = input.nextLine();
System.out.println(getStudent(enrolledStudents, studentSearch));
input.close(); //close the scanner
}
public static String[] getStudentAttendance(int studentAmount) {
String[] enrolledStudents = new String[studentAmount];
System.out.println("Input the students names:");
for (int count = 0; count < enrolledStudents.length; count++) {
System.out.print((count + 1) + ".) ");
enrolledStudents[count] = input.nextLine();
}
return enrolledStudents;
}
public static String getStudent(String[] enrolledStudents, String studentSearch) {
boolean flag = false; //added flag, this will be true if name is found
//otherwise false
for (int count = 0; count < enrolledStudents.length; count++) {
if (studentSearch.equals(enrolledStudents[count])) {
flag = true;
break; //if name is found breaking the loop.
} else {
flag = false;
}
}
if (flag == true) //checking the flag here
return studentSearch + " is present in the class";
else
return studentSearch + " is not present in the class: ";
}
}
I am getting below result after running my code.
Looks like you already got the idea how to search using .equals() method. Assuming you'll fix getStudent() method by handling "not found" situation, you should be done.
Next, do you want to improve your search, is that your real question? That depends on what type of search do you want to implement. Partial name match, name starts with, ignoring upper/lower case, wildcard search are different options. If that is what you want, please add it to the question.
so my problem is that I need to get the user to enter a string. then they will enter a character that they want counted. So the program is supposed to count how many times the character they entered will appear in the string, this is my issue. If someone can give me some information as to how to do this, it'll be greatly appreciated.
import java.util.Scanner;
public class LetterCounter {
public static void main(String[] args) {
Scanner keyboard= new Scanner(System.in);
System.out.println("please enter a word");//get the word from the user
String word= keyboard.nextLine();
System.out.println("Enter a character");//Ask the user to enter the character they wan counted in the string
String character= keyboard.nextLine();
}
}
Here is a solution taken from this previously asked question and edited to better fit your situation.
Either have the user enter a char, or take the first character from
the string they entered using character.chatAt(0).
Use word.length to figure out how long the string is
Create a for loop and use word.charAt() to count how many times your character appears.
System.out.println("please enter a word");//get the word from the user
String word= keyboard.nextLine();
System.out.println("Enter a character");//Ask the user to enter the character they want counted in the string
String character = keyboard.nextLine();
char myChar = character.charAt(0);
int charCount = 0;
for (int i = 1; i < word.length();i++)
{
if (word.charAt(i) == myChar)
{
charCount++;
}
}
System.out.printf("It appears %d times",charCount);
This should do it. What it does is that it gets a string to look at, gets a character to look at, iterates through the string looking for matches, counts the number of matches, and then returns the information. There are more elegant ways to do this (for example, using a regex matcher would also work).
#SuppressWarnings("resource") Scanner scanner = new Scanner(System.in);
System.out.print("Enter a string:\t");
String word = scanner.nextLine();
System.out.print("Enter a character:\t");
String character = scanner.nextLine();
char charVar = 0;
if (character.length() > 1) {
System.err.println("Please input only one character.");
} else {
charVar = character.charAt(0);
}
int count = 0;
for (char x : word.toCharArray()) {
if (x == charVar) {
count++;
}
}
System.out.println("Character " + charVar + " appears " + count + (count == 1 ? " time" : " times"));
So first of all, hello everyone this is my first time stackoverflow as a question asker and I know you folks don't like people asking homework questions on here but I've been struggling with this for about a week now and have given it several reasonable attempts so I actually need help here and am not just trying to mooch answers off you amazing coders :)
So my task at hand is I'm trying (the language is java btw) to find the number of times a letter (which the user inputs) occurs in a word (which the user also picks, and then to output the number of time that word occurs, for example: the word hello has two 'l's in it.. it should be pretty easy but for some reason I can't get it :/
I believe using my current code the variable "let" gets turned into an ascii character and idk what to do with that, or rather how I should compare it with all the other characters in the word.
Please help :)
import java.util.Scanner;
public class LetterCounter {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
String word = "";
String letter;
int limit = 0;
String input = null;
String let;
int count = 0;
int j = 0;
while(limit == 0){
System.out.println("Type a word.");
word = scan.nextLine();
System.out.println("Type a single letter.");
letter = scan.nextLine();
let = letter.substring(0,1);
char car;
while(j<word.length()){
car = word.charAt(j);
for(int x=1; x==j; x++){
if(let.charAt(0)==car){
count ++;
}
}
j+=1;
}
System.out.println(count + " " + "occurances.");
}
}
}
Here is a sample code that should work
import java.util.Scanner;
public class LetterCounter {
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
System.out.println("Type a word.");
String word = scan.nextLine();
System.out.println("Type a single letter.");
String letter = scan.nextLine();
char let = letter.charAt(0);
int count = 0;
for (char char1: word.toCharArray()) {
if (char1 == let) {
count++;
}
}
System.out.println(count + " " + "occurrences.");
}
}
Here is the test output
Type a word.
letter
Type a single letter.
t
2 occurrences.
I have wrote this code and now i'm practicing and i'm trying it to write it in a different or more efficient way. Basically this code asks the user to enter a word and the second player guesses the letters of the word with 6 tries and at the end there is one last chance to guess the whole entire word. Any suggestions on how i can write this code in a simple way?
static int NUM_OF_TRIES = 6;
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
System.out.println("Player 1 please enter the word");
String word = keyboard.next();
for (int i = 0; i < NUM_OF_TRIES; i++) {
System.out.println("Enter your guess please");
String guess = keyboard.next();
boolean a = true;
for (int j = 0; j < word.length(); j++) {
if (guess.charAt(0) == word.charAt(j)) {
System.out.println(" at position " + (j + 1));
a = false;
break;
}
}
if (a) {
System.out.println("Sorry not letter " + guess.charAt(0));
continue;
}
}
System.out.println("Enter your last guess: ");
String wordComp;
wordComp = keyboard.next();
if (wordComp.equals(word)) {
System.out.println("You got it!");
} else {
System.out.println("Sorry you lost!");
}
}
}
Well, here is a shorter version:
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
System.out.println("Player 1 please enter the word");
String word = keyboard.next();
for (int i = 0; i < NUM_OF_TRIES; i++) {
System.out.println("Enter your guess please");
String guess = keyboard.next();
int index = word.indexOf(guess.charAt(0));
if (index == -1)
System.out.println("Sorry not letter " + guess.charAt(0));
else
System.out.println(" at position " + (index + 1));
}
System.out.println("Enter your last guess: ");
String wordComp = keyboard.next();
if (wordComp.equals(word))
System.out.println("You got it!");
else
System.out.println("Sorry you lost!");
}
---First of all you'll have to ensure that
word.length <=guess.length
or you'll run into an exception.--- edit: that was obv not correct
Can't test right now bc I'm on my mobile, but as far as I can see, you'll run into problems if the word to guess has the same letter multiple times, since you're breaking out of the loop after finding the equal first letter.
As mentioned in comments, the comparison could be done by a method like
private static List<Integer> getLetterIndices(String word, char letter);
Then you won't need your boolean to indicate correct guesses, but a list of indices found
And of course you can do an object oriented approach instead of the static main method (not that it's faster to implement or better performance, just for practicing), perhaps something in the lines of this:
public class WordToGuess{
private Map<Character,List<Integer>> letter2indices;//...
public WordToGuess(String word){
parseIndices(word);
}
//parse indices of each letter to the map
private void parseIndices(String word);
public List<Integer> getLetterIndices(char letter);
}