Merge branch 'master' into BAEL-16633

java-numbers-2/src/main/java/com/baeldung/algorithms/primechecker/BigIntegerPrimeChecker.java

@@ -0,0 +1,13 @@
+package com.baeldung.algorithms.primechecker;
+
+import java.math.BigInteger;
+
+public class BigIntegerPrimeChecker implements PrimeChecker<Long>{
+
+    @Override
+    public boolean isPrime(Long number) {
+        BigInteger bigInt = BigInteger.valueOf(number);
+        return bigInt.isProbablePrime(100);
+    }
+
+}

java-numbers-2/src/main/java/com/baeldung/algorithms/primechecker/BruteForcePrimeChecker.java

@@ -0,0 +1,14 @@
+package com.baeldung.algorithms.primechecker;
+
+import java.util.stream.IntStream;
+
+public class BruteForcePrimeChecker implements PrimeChecker<Integer> {
+
+    @Override
+    public boolean isPrime(Integer number) {
+
+        return number > 2 ? IntStream.range(2, number)
+            .noneMatch(n -> (number % n == 0)) : false;
+    }
+
+}

java-numbers-2/src/main/java/com/baeldung/algorithms/primechecker/OptimisedPrimeChecker.java

@@ -0,0 +1,13 @@
+package com.baeldung.algorithms.primechecker;
+
+import java.util.stream.IntStream;
+
+public class OptimisedPrimeChecker implements PrimeChecker<Integer> {
+
+    @Override
+    public boolean isPrime(Integer number) {
+        return number > 2 ? IntStream.rangeClosed(2, (int) Math.sqrt(number))
+            .noneMatch(n -> (number % n == 0)) : false;
+    }
+
+}

java-numbers-2/src/main/java/com/baeldung/algorithms/primechecker/PrimeChecker.java

@@ -0,0 +1,6 @@
+package com.baeldung.algorithms.primechecker;
+
+public interface PrimeChecker <T> {
+    
+    public boolean isPrime( T number );
+}

java-numbers-2/src/main/java/com/baeldung/algorithms/primechecker/PrimesPrimeChecker.java

@@ -0,0 +1,12 @@
+package com.baeldung.algorithms.primechecker;
+
+import org.apache.commons.math3.primes.Primes;
+
+public class PrimesPrimeChecker implements PrimeChecker<Integer>{
+
+    @Override
+    public boolean isPrime(Integer number) {
+        return Primes.isPrime(number);
+    }
+
+}

java-numbers-2/src/main/java/com/baeldung/area/circle/Circle.java

@@ -0,0 +1,26 @@
+package com.baeldung.area.circle;
+
+public class Circle {
+
+    private double radius;
+
+    public Circle(double radius) {
+        this.radius = radius;
+    }
+
+    public double getRadius() {
+        return radius;
+    }
+
+    public void setRadius(double radius) {
+        this.radius = radius;
+    }
+
+    private double calculateArea() {
+        return radius * radius * Math.PI;
+    }
+
+    public String toString() {
+        return "The area of the circle [radius = " + radius + "]: " + calculateArea();
+    }
+}

java-numbers-2/src/main/java/com/baeldung/area/circle/CircleArea.java

@@ -0,0 +1,36 @@
+package com.baeldung.area.circle;
+
+import java.util.InputMismatchException;
+import java.util.Scanner;
+
+public class CircleArea {
+
+    public static void main(String[] args) {
+        if (args.length > 0) {
+            try {
+                double radius = Double.parseDouble(args[0]);
+                calculateArea(radius);
+            } catch (NumberFormatException nfe) {
+                System.out.println("Invalid value for radius");
+                System.exit(0);
+            }
+        }
+
+        try (Scanner scanner = new Scanner(System.in)) {
+            System.out.println("Please enter radius value: ");
+            double radius = scanner.nextDouble();
+            calculateArea(radius);
+        } catch (InputMismatchException e) {
+            System.out.println("Invalid value for radius");
+            System.exit(0);
+        }
+
+        Circle circle = new Circle(7);
+        System.out.println(circle);
+    }
+
+    private static void calculateArea(double radius) {
+        double area = radius * radius * Math.PI;
+        System.out.println("The area of the circle [radius = " + radius + "]: " + area);
+    }
+}

java-numbers-2/src/main/java/com/baeldung/binarynumbers/BinaryNumbers.java

@@ -0,0 +1,140 @@
+package com.baeldung.binarynumbers;
+
+public class BinaryNumbers {
+
+    /**
+     * This method takes a decimal number and convert it into a binary number.
+     * example:- input:10, output:1010
+     *
+     * @param decimalNumber
+     * @return binary number
+     */
+    public Integer convertDecimalToBinary(Integer decimalNumber) {
+
+        if (decimalNumber == 0) {
+            return decimalNumber;
+        }
+
+        StringBuilder binaryNumber = new StringBuilder();
+        Integer quotient = decimalNumber;
+
+        while (quotient > 0) {
+
+            int remainder = quotient % 2;
+            binaryNumber.append(remainder);
+            quotient /= 2;
+        }
+
+        binaryNumber = binaryNumber.reverse();
+        return Integer.valueOf(binaryNumber.toString());
+    }
+
+    /**
+     * This method takes a binary number and convert it into a decimal number.
+     * example:- input:101, output:5
+     *
+     * @param binary number
+     * @return decimal Number
+     */
+    public Integer convertBinaryToDecimal(Integer binaryNumber) {
+
+        Integer decimalNumber = 0;
+        Integer base = 1;
+
+        while (binaryNumber > 0) {
+
+            int lastDigit = binaryNumber % 10;
+            binaryNumber = binaryNumber / 10;
+
+            decimalNumber += lastDigit * base;
+            base = base * 2;
+        }
+        return decimalNumber;
+    }
+
+    /**
+     * This method accepts two binary numbers and returns sum of input numbers.
+     * Example:- firstNum: 101, secondNum: 100, output: 1001
+     *
+     * @param firstNum
+     * @param secondNum
+     * @return addition of input numbers
+     */
+    public Integer addBinaryNumber(Integer firstNum, Integer secondNum) {
+
+        StringBuilder output = new StringBuilder();
+
+        int carry = 0;
+        int temp;
+
+        while (firstNum != 0 || secondNum != 0) {
+
+            temp = (firstNum % 10 + secondNum % 10 + carry) % 2;
+            output.append(temp);
+
+            carry = (firstNum % 10 + secondNum % 10 + carry) / 2;
+
+            firstNum = firstNum / 10;
+            secondNum = secondNum / 10;
+        }
+
+        if (carry != 0) {
+            output.append(carry);
+        }
+
+        return Integer.valueOf(output.reverse()
+            .toString());
+    }
+
+    /**
+    * This method takes two binary number as input and subtract second number from the first number.
+    * example:- firstNum: 1000, secondNum: 11, output: 101
+    * @param firstNum
+    * @param secondNum
+    * @return Result of subtraction of secondNum from first
+    */
+    public Integer substractBinaryNumber(Integer firstNum, Integer secondNum) {
+
+        int onesComplement = Integer.valueOf(getOnesComplement(secondNum));
+        StringBuilder output = new StringBuilder();
+        int carry = 0;
+        int temp;
+
+        while (firstNum != 0 || onesComplement != 0) {
+
+            temp = (firstNum % 10 + onesComplement % 10 + carry) % 2;
+            output.append(temp);
+
+            carry = (firstNum % 10 + onesComplement % 10 + carry) / 2;
+
+            firstNum = firstNum / 10;
+            onesComplement = onesComplement / 10;
+        }
+
+        String additionOfFirstNumAndOnesComplement = output.reverse()
+            .toString();
+
+        if (carry == 1) {
+            return addBinaryNumber(Integer.valueOf(additionOfFirstNumAndOnesComplement), carry);
+        } else {
+            return getOnesComplement(Integer.valueOf(additionOfFirstNumAndOnesComplement));
+        }
+    }
+
+    public Integer getOnesComplement(Integer num) {
+
+        StringBuilder onesComplement = new StringBuilder();
+        while (num > 0) {
+            int lastDigit = num % 10;
+            if (lastDigit == 0) {
+                onesComplement.append(1);
+            } else {
+                onesComplement.append(0);
+            }
+            num = num / 10;
+        }
+        return Integer.valueOf(onesComplement.reverse()
+            .toString());
+    }
+
+}

java-numbers-2/src/main/java/com/baeldung/lcm/BigIntegerLCM.java

@@ -0,0 +1,13 @@
+package com.baeldung.lcm;
+
+import java.math.BigInteger;
+
+public class BigIntegerLCM {
+
+    public static BigInteger lcm(BigInteger number1, BigInteger number2) {
+        BigInteger gcd = number1.gcd(number2);
+        BigInteger absProduct = number1.multiply(number2).abs();
+        return absProduct.divide(gcd);
+    }
+
+}

java-numbers-2/src/main/java/com/baeldung/lcm/EuclideanAlgorithm.java

@@ -0,0 +1,40 @@
+package com.baeldung.lcm;
+
+import java.util.Arrays;
+
+public class EuclideanAlgorithm {
+
+    public static int gcd(int number1, int number2) {
+        if (number1 == 0 || number2 == 0) {
+            return number1 + number2;
+        } else {
+            int absNumber1 = Math.abs(number1);
+            int absNumber2 = Math.abs(number2);
+            int biggerValue = Math.max(absNumber1, absNumber2);
+            int smallerValue = Math.min(absNumber1, absNumber2);
+            return gcd(biggerValue % smallerValue, smallerValue);
+        }
+    }
+
+    public static int lcm(int number1, int number2) {
+        if (number1 == 0 || number2 == 0)
+            return 0;
+        else {
+            int gcd = gcd(number1, number2);
+            return Math.abs(number1 * number2) / gcd;
+        }
+    }
+
+    public static int lcmForArray(int[] numbers) {
+        int lcm = numbers[0];
+        for (int i = 1; i <= numbers.length - 1; i++) {
+            lcm = lcm(lcm, numbers[i]);
+        }
+        return lcm;
+    }
+
+    public static int lcmByLambda(int... numbers) {
+        return Arrays.stream(numbers).reduce(1, (lcmSoFar, currentNumber) -> Math.abs(lcmSoFar * currentNumber) / gcd(lcmSoFar, currentNumber));
+    }
+
+}

java-numbers-2/src/main/java/com/baeldung/lcm/PrimeFactorizationAlgorithm.java

@@ -0,0 +1,42 @@
+package com.baeldung.lcm;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+public class PrimeFactorizationAlgorithm {
+
+    public static Map<Integer, Integer> getPrimeFactors(int number) {
+        int absNumber = Math.abs(number);
+        Map<Integer, Integer> primeFactorsMap = new HashMap<Integer, Integer>();
+        for (int factor = 2; factor <= absNumber; factor++) {
+            while (absNumber % factor == 0) {
+                Integer power = primeFactorsMap.get(factor);
+                if (power == null) {
+                    power = 0;
+                }
+                primeFactorsMap.put(factor, power + 1);
+                absNumber /= factor;
+            }
+        }
+        return primeFactorsMap;
+    }
+
+    public static int lcm(int number1, int number2) {
+        if (number1 == 0 || number2 == 0) {
+            return 0;
+        }
+        Map<Integer, Integer> primeFactorsForNum1 = getPrimeFactors(number1);
+        Map<Integer, Integer> primeFactorsForNum2 = getPrimeFactors(number2);
+        Set<Integer> primeFactorsUnionSet = new HashSet<Integer>(primeFactorsForNum1.keySet());
+        primeFactorsUnionSet.addAll(primeFactorsForNum2.keySet());
+        int lcm = 1;
+        for (Integer primeFactor : primeFactorsUnionSet) {
+            lcm *= Math.pow(primeFactor, Math.max(primeFactorsForNum1.getOrDefault(primeFactor, 0),
+                    primeFactorsForNum2.getOrDefault(primeFactor, 0)));
+        }
+        return lcm;
+    }
+
+}

java-numbers-2/src/main/java/com/baeldung/lcm/SimpleAlgorithm.java

@@ -0,0 +1,18 @@
+package com.baeldung.lcm;
+
+public class SimpleAlgorithm {
+    public static int lcm(int number1, int number2) {
+        if (number1 == 0 || number2 == 0) {
+            return 0;
+        }
+        int absNumber1 = Math.abs(number1);
+        int absNumber2 = Math.abs(number2);
+        int absHigherNumber = Math.max(absNumber1, absNumber2);
+        int absLowerNumber = Math.min(absNumber1, absNumber2);
+        int lcm = absHigherNumber;
+        while (lcm % absLowerNumber != 0) {
+            lcm += absHigherNumber;
+        }
+        return lcm;
+    }
+}

java-numbers-2/src/main/java/com/baeldung/nan/NaNExample.java

@@ -0,0 +1,81 @@
+package com.baeldung.nan;
+
+/**
+ * Sample usage of NaN.
+ *
+ */
+public class NaNExample {
+
+    public static void main(String[] args) {
+        NaNExample naNExample = new NaNExample();
+        naNExample.demo();
+    }
+
+    void demo() {
+        undefined_operations_produce_NaN();
+        operations_with_no_real_results_produce_NaN();
+        operations_with_NaN_produce_NaN();
+        comparison_with_NaN();
+        check_if_a_value_is_NaN();
+        assign_NaN_to_missing_values();
+    }
+
+    void undefined_operations_produce_NaN() {
+        System.out.println("Undefined Operations Produce NaN");
+        final double ZERO = 0;
+        System.out.println("ZERO / ZERO = " + (ZERO / ZERO));
+        System.out.println("INFINITY - INFINITY = " + (Double.POSITIVE_INFINITY - Double.POSITIVE_INFINITY));
+        System.out.println("INFINITY * ZERO = " + (Double.POSITIVE_INFINITY * ZERO));
+        System.out.println();
+    }
+
+    void operations_with_no_real_results_produce_NaN() {
+        System.out.println("Operations with no real results produce NaN");
+        System.out.println("SQUARE ROOT OF -1 = " + Math.sqrt(-1));
+        System.out.println("LOG OF -1 = " + Math.log(-1));
+        System.out.println();
+    }
+
+    void operations_with_NaN_produce_NaN() {
+        System.out.println("Operations with NaN produce NaN");
+        System.out.println("2 + NaN = " + (2 + Double.NaN));
+        System.out.println("2 - NaN = " + (2 - Double.NaN));
+        System.out.println("2 * NaN = " + (2 * Double.NaN));
+        System.out.println("2 / NaN = " + (2 / Double.NaN));
+        System.out.println();
+    }
+
+    void assign_NaN_to_missing_values() {
+        System.out.println("Assign NaN to Missing values");
+        double salaryRequired = Double.NaN;
+        System.out.println(salaryRequired);
+        System.out.println();
+    }
+
+    void comparison_with_NaN() {
+        System.out.println("Comparison with NaN");
+        final double NAN = Double.NaN;
+        System.out.println("NaN == 1 = " + (NAN == 1));
+        System.out.println("NaN > 1 = " + (NAN > 1));
+        System.out.println("NaN < 1 = " + (NAN < 1));
+        System.out.println("NaN != 1 = " + (NAN != 1));
+        System.out.println("NaN == NaN = " + (NAN == NAN));
+        System.out.println("NaN > NaN = " + (NAN > NAN));
+        System.out.println("NaN < NaN = " + (NAN < NAN));
+        System.out.println("NaN != NaN = " + (NAN != NAN));
+        System.out.println();
+    }
+
+    void check_if_a_value_is_NaN() {
+        System.out.println("Check if a value is NaN");
+        double x = 1;
+        System.out.println(x + " is NaN = " + (x != x));
+        System.out.println(x + " is NaN = " + (Double.isNaN(x)));
+
+        x = Double.NaN;
+        System.out.println(x + " is NaN = " + (x != x));
+        System.out.println(x + " is NaN = " + (Double.isNaN(x)));
+        System.out.println();
+    }
+
+}

java-numbers-2/src/main/java/com/baeldung/numbersinrange/NumbersInARange.java

@@ -0,0 +1,36 @@
+package com.baeldung.numbersinrange;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+public class NumbersInARange {
+
+    public List<Integer> getNumbersInRange(int start, int end) {
+        List<Integer> result = new ArrayList<>();
+        for (int i = start; i < end; i++) {
+            result.add(i);
+        }
+        return result;
+    }
+
+    public List<Integer> getNumbersUsingIntStreamRange(int start, int end) {
+        return IntStream.range(start, end)
+          .boxed()
+          .collect(Collectors.toList());
+    }
+
+    public List<Integer> getNumbersUsingIntStreamRangeClosed(int start, int end) {
+        return IntStream.rangeClosed(start, end)
+          .boxed()
+          .collect(Collectors.toList());
+    }
+
+    public List<Integer> getNumbersUsingIntStreamIterate(int start, int limit) {
+        return IntStream.iterate(start, i -> i + 1)
+          .limit(limit)
+          .boxed()
+          .collect(Collectors.toList());
+    }
+}

java-numbers-2/src/main/java/com/baeldung/numbersinrange/RandomNumbersInARange.java

@@ -0,0 +1,22 @@
+package com.baeldung.numbersinrange;
+
+import java.util.Random;
+
+public class RandomNumbersInARange {
+
+    public int getRandomNumber(int min, int max) {
+        return (int) ((Math.random() * (max - min)) + min);
+    }
+
+    public int getRandomNumberUsingNextInt(int min, int max) {
+        Random random = new Random();
+        return random.nextInt(max - min) + min;
+    }
+
+    public int getRandomNumberUsingInts(int min, int max) {
+        Random random = new Random();
+        return random.ints(min, max)
+          .findFirst()
+          .getAsInt();
+    }
+}

java-numbers-2/src/main/java/com/baeldung/pow/PowerExample.java

@@ -0,0 +1,19 @@
+package com.baeldung.pow;
+
+import java.text.DecimalFormat;
+
+public class PowerExample {
+
+    public static void main(String[] args) {
+
+        int intResult = (int) Math.pow(2, 3);
+        System.out.println("Math.pow(2, 3) = " + intResult);
+
+        double dblResult = Math.pow(4.2, 3);
+        System.out.println("Math.pow(4.2, 3) = " + Math.pow(4.2, 3));
+
+        DecimalFormat df = new DecimalFormat(".00");
+        System.out.println("Math.pow(4.2, 3) rounded = " + df.format(dblResult));
+
+    }
+}

java-numbers-2/src/main/java/com/baeldung/prime/PrimeGenerator.java

@@ -0,0 +1,59 @@
+package com.baeldung.prime;
+
+import java.util.Arrays;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+public class PrimeGenerator {
+    public static List<Integer> sieveOfEratosthenes(int n) {
+        final boolean prime[] = new boolean[n + 1];
+        Arrays.fill(prime, true);
+
+        for (int p = 2; p * p <= n; p++) {
+            if (prime[p]) {
+                for (int i = p * 2; i <= n; i += p)
+                    prime[i] = false;
+            }
+        }
+
+        final List<Integer> primes = new LinkedList<>();
+        for (int i = 2; i <= n; i++) {
+            if (prime[i])
+                primes.add(i);
+        }
+        return primes;
+    }
+
+    public static List<Integer> primeNumbersBruteForce(int max) {
+        final List<Integer> primeNumbers = new LinkedList<Integer>();
+        for (int i = 2; i <= max; i++) {
+            if (isPrimeBruteForce(i)) {
+                primeNumbers.add(i);
+            }
+        }
+        return primeNumbers;
+    }
+
+    private static boolean isPrimeBruteForce(int x) {
+        for (int i = 2; i < x; i++) {
+            if (x % i == 0) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    public static List<Integer> primeNumbersTill(int max) {
+        return IntStream.rangeClosed(2, max)
+            .filter(x -> isPrime(x))
+            .boxed()
+            .collect(Collectors.toList());
+    }
+
+    private static boolean isPrime(int x) {
+        return IntStream.rangeClosed(2, (int) (Math.sqrt(x)))
+            .allMatch(n -> x % n != 0);
+    }
+}