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6x6 Covariance Matrix Conversion from ENU to ECEF

Jan 28, 2023AustinLeath
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More Java Posts

Random Integers -> file

Nov 19, 2022CodeCatch

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//sample code to write 100 random ints to a file, 1 per line
import java.io.PrintStream;
import java.io.IOException;
import java.io.File;
import java.util.Random;
public class WriteToFile {
public static void main(String[] args) {
try {
PrintStream writer = new PrintStream(new File("randInts.txt"));
Random r = new Random();
final int LIMIT = 100;
for (int i = 0; i < LIMIT; i++) {
writer.println(r.nextInt());
}
writer.close();
} catch (IOException e) {
System.out.println("An error occured while trying to write to the file");
}
}
}

Send Email from Java

Nov 19, 2022CodeCatch

0 likes • 3 views

import javax.mail.*;
import javax.mail.internet.*;
import java.util.*;
public void postMail( String recipients[ ], String subject, String message , String from) throws MessagingException
{
boolean debug = false;
//Set the host smtp address
Properties props = new Properties();
props.put("mail.smtp.host", "smtp.example.com");
// create some properties and get the default Session
Session session = Session.getDefaultInstance(props, null);
session.setDebug(debug);
// create a message
Message msg = new MimeMessage(session);
// set the from and to address
InternetAddress addressFrom = new InternetAddress(from);
msg.setFrom(addressFrom);
InternetAddress[] addressTo = new InternetAddress[recipients.length];
for (int i = 0; i < recipients.length; i++)
{
addressTo[i] = new InternetAddress(recipients[i]);
}
msg.setRecipients(Message.RecipientType.TO, addressTo);
// Optional : You can also set your custom headers in the Email if you Want
msg.addHeader("MyHeaderName", "myHeaderValue");
// Setting the Subject and Content Type
msg.setSubject(subject);
msg.setContent(message, "text/plain");
Transport.send(msg);
}

Word Counter

Nov 19, 2022CodeCatch

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import java.io.File;
import java.io.IOException;
import java.util.Map;
import java.util.Scanner;
import java.util.TreeMap;
public class SimpleWordCounter {
public static void main(String[] args) {
try {
File f = new File("ciaFactBook2008.txt");
Scanner sc;
sc = new Scanner(f);
// sc.useDelimiter("[^a-zA-Z']+");
Map<String, Integer> wordCount = new TreeMap<String, Integer>();
while(sc.hasNext()) {
String word = sc.next();
if(!wordCount.containsKey(word))
wordCount.put(word, 1);
else
wordCount.put(word, wordCount.get(word) + 1);
}
// show results
for(String word : wordCount.keySet())
System.out.println(word + " " + wordCount.get(word));
System.out.println(wordCount.size());
}
catch(IOException e) {
System.out.println("Unable to read from file.");
}
}
}

WordleSolver

Feb 1, 2022LeifMessinger

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//Leif Messinger
//Solves wordle
//Needs a list of wordle words, newline separated and 5 characters each
import java.util.*;
import java.io.File;
import java.io.FileNotFoundException;
class WordleSolver {
public static void printPointer(int position){
for(int i = 0; i < position; ++i){
System.out.print(" ");
}
System.out.print("^");
}
public static void main(String[] args) throws FileNotFoundException{
if(args.length < 1) return;
File dictionary = new File(args[0]);
Scanner sc = new Scanner(dictionary);
ArrayList<String> possibleWords = new ArrayList<String>();
while(sc.hasNextLine()){
possibleWords.add(sc.nextLine());
}
Scanner input = new Scanner(System.in);
while(possibleWords.size() > 0){
//Choose a word out of the possible words
final int randomIndex = (int)(Math.random() * possibleWords.size());
String chosenWord = possibleWords.get(randomIndex);
possibleWords.remove(randomIndex);
System.out.println("Is it correct?");
for(int i = 0; i < chosenWord.length(); ++i){
System.out.println(chosenWord);
printPointer(i);
System.out.println(" y/n?");
if(input.nextLine().toLowerCase().contains("y")){
//Filter by correct character
for(int possibleWord = possibleWords.size() - 1; possibleWord >= 0; --possibleWord){ //Has to be backwards for removing entries, also has to be int not unsigned
if(possibleWords.get(possibleWord).charAt(i) != chosenWord.charAt(i)){
possibleWords.remove(possibleWord);
}
}
}
}
System.out.println("Is it misplaced?");
//Stores a count of every letter misplaced
short[] misplacedCounts = new short[('z'-'a')+1]; //Praise be the garbage collector
for(int i = 0; i < chosenWord.length(); ++i){
System.out.println(chosenWord);
printPointer(i);
System.out.println(" y/n?");
if(input.nextLine().toLowerCase().contains("y")){
//Filter to make sure there's at least as many letters as needed
++misplacedCounts[(chosenWord.charAt(i) - 'a') - 1];
for(int possibleWord = possibleWords.size() - 1; possibleWord >= 0; --possibleWord){ //Has to be backwards for removing entries, also has to be int not unsigned
int count = 0;
for(int j = 0; j < possibleWords.get(possibleWord).length(); ++j){
if(possibleWords.get(possibleWord).charAt(j) == chosenWord.charAt(i))
++count;
}
//If there's not enough of the character that we need, then we remove that from the list of possible characters
if(count < misplacedCounts[(chosenWord.charAt(i) - 'a') - 1]){
possibleWords.remove(possibleWord);
}
}
//Also filter out words where that letter doesn't belong there
for(int possibleWord = possibleWords.size() - 1; possibleWord >= 0; --possibleWord){ //Has to be backwards for removing entries, also has to be int not unsigned
if(possibleWords.get(possibleWord).charAt(i) == chosenWord.charAt(i)){
possibleWords.remove(possibleWord);
continue; //Breaks the current word and moves on in the loop
}
}
}
}
}
}
}

try-catch modularity

Jan 31, 2023AustinLeath

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public class UserService {
private UserRepository userRepository;
public UserService(UserRepository userRepository) {
this.userRepository = userRepository;
}
public User getUserById(long id) {
try {
return userRepository.getUserById(id);
} catch (Exception e) {
// Log the exception here
System.out.println("An error occurred while fetching the user: " + e.getMessage());
return null;
}
}
}
public class UserRepository {
public User getUserById(long id) throws Exception {
// Database query to fetch the user
if (id < 0) {
throw new Exception("Invalid user id");
}
// Return the user object
return new User(id, "John Doe");
}
}
public class User {
private long id;
private String name;
public User(long id, String name) {
this.id = id;
this.name = name;
}
public long getId() {
return id;
}
public String getName() {
return name;
}
}

quick sort

Nov 19, 2022CodeCatch

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import java.util.Arrays;
public class QuickSortMain {
private static int array[];
public static void sort(int[] arr) {
if (arr == null || arr.length == 0) {
return;
}
array = arr;
quickSort(0, array.length-1);
}
private static void quickSort(int left, int right) {
int i = left;
int j = right;
// find pivot number, we will take it as mid
int pivot = array[left+(right-left)/2];
while (i <= j) {
/**
* In each iteration, we will increment left until we find element greater than pivot
* We will decrement right until we find element less than pivot
*/
while (array[i] < pivot) { i++; } while (array[j] > pivot) {
j--;
}
if (i <= j) {
exchange(i, j);
//move index to next position on both sides
i++;
j--;
}
}
// call quickSort() method recursively
if (left < j)
quickSort(left, j);
if (i < right)
quickSort(i, right);
}
private static void exchange(int i, int j) {
int temp = array[i];
array[i] = array[j];
array[j] = temp;
}
public static void main(String a[]){
int[] input = {33,21,45,64,55,34,11,8,3,5,1};
System.out.println("Before Sorting : ");
System.out.println(Arrays.toString(input));
sort(input);
System.out.println("==================");
System.out.println("After Sorting : ");
System.out.println(Arrays.toString(array));
}
}