London | 26-Java-Jun | Elhadj Abdoul Diallo | Sprint 1 | Backlog Exercises

.gitignore

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+.idea
+target

track/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>traiing</groupId>
+    <artifactId>track</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <maven.compiler.source>26</maven.compiler.source>
+        <maven.compiler.target>26</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+</project>

track/src/main/java/training/sprint1/backlog/prime_numbers/PrimeNumbers.java

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+package training.sprint1.backlog.prime_numbers;
+
+/**
+ * Exercise
+ * Create a private method to print all prime numbers up to 1000. Call this
+ * from a main method. Remember to use sensible method and variable names,
+ * and add documentation where necessary! Remember to use the debugger if something goes wrong!
+ */
+public class PrimeNumbers {
+    /**
+     * Checks if a divisor is a perfect factor of a target number.
+     */
+    private boolean isFactor(int target, int divisor) {
+        return target % divisor == 0;
+    }
+
+    /**
+     * Checks whether a given int is a prime number ( a whole number greater than 1 that has exactly two factors: 1 and itself)
+     *
+     * @param num the whole number to check
+     * @return a boolean value, true if prime, false otherwise.
+     */
+    private boolean isPrime(int num) {
+        if (num <= 1) return false;
+        if (num == 2) return true;
+        if (isFactor(num, 2)) return false; // even numbers are not prime numbers a part from 2.
+
+        int factor = 3;
+        while (factor * factor <= num) {
+            if (isFactor(num, factor)) return false;
+            factor += 2; // make sure we only check odd numbers
+        }
+        return true;
+    }
+
+    private void printPrimeNumbersUpTo1000() {
+        for (int i = 1; i <= 1000; i++) {
+            if (isPrime(i)) {
+                System.out.println(i);
+            }
+        }
+    }
+
+    public static void main(String[] args) {
+        new PrimeNumbers().printPrimeNumbersUpTo1000();
+    }
+}

track/src/main/java/training/sprint1/backlog/reverse_numbers/NumberReverser.java

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+package training.sprint1.backlog.reverse_numbers;
+
+/**
+ * Create a private method that accepts a number as an argument and returns the number in reverse.
+ * For example, an input of 3956 should return 6593. Create code to call this from a main method. Remember
+ * to use sensible method and variable names, and add documentation. Remember to use the debugger if something goes wrong!
+ */
+public class NumberReverser {
+    /**
+     * reverses the digits of an integer using Math.log10 to determine loop count.
+     *
+     * @param num The integer to be reversed
+     * @return The reversed integer
+     * @implNote this method assumes that the input fits within
+     * the integer boundaries and does not account for overflow with Integer.MAX_VALUE.
+     */
+    private int reverseInteger(int num) {
+        int reversed = 0;
+
+        int digitCount = (int) Math.log10(Math.abs(num)) + 1;
+
+        for (int i = 0; i < digitCount; i++) {
+            int lastDigit = num % 10;
+            reversed = (reversed * 10) + lastDigit;
+            num = num / 10;
+        }
+
+        return reversed;
+    }
+
+    public static void main(String[] args) {
+        NumberReverser reverseNumbers = new NumberReverser();
+        int reversedNumber = reverseNumbers.reverseInteger(-994994);
+        int reversedNumber1 = reverseNumbers.reverseInteger(0);
+        System.out.println(reversedNumber);
+        System.out.println(reversedNumber1);
+    }
+}