style: enable MultipleVariableDeclarations in checkstyle (TheAlgorithms#5175)

Co-authored-by: vaibhav <vaibhav.waghmare@techprescient.com>

Author: vaibhav9t1

checkstyle.xml

@@ -167,7 +167,7 @@
     <module name="InnerAssignment"/>
     <!-- TODO <module name="MagicNumber"/> -->
     <!-- TODO <module name="MissingSwitchDefault"/> -->
-    <!-- TODO <module name="MultipleVariableDeclarations"/> -->
+    <module name="MultipleVariableDeclarations"/>
     <module name="SimplifyBooleanExpression"/>
     <module name="SimplifyBooleanReturn"/>
 

src/main/java/com/thealgorithms/backtracking/PowerSum.java

@@ -8,7 +8,8 @@
  */
 public class PowerSum {
 
-    private int count = 0, sum = 0;
+    private int count = 0;
+    private int sum = 0;
 
     public int powSum(int N, int X) {
         Sum(N, X, 1);

src/main/java/com/thealgorithms/ciphers/Blowfish.java

@@ -1175,7 +1175,8 @@ private void keyGenerate(String key) {
 
     // round function
     private String round(int time, String plainText) {
-        String left, right;
+        String left;
+        String right;
         left = plainText.substring(0, 8);
         right = plainText.substring(8, 16);
         left = xor(left, P[time]);

src/main/java/com/thealgorithms/ciphers/DES.java

@@ -74,13 +74,15 @@ public void setKey(String key) {
 
     private String[] getSubkeys(String originalKey) {
         StringBuilder permutedKey = new StringBuilder(); // Initial permutation of keys via pc1
-        int i, j;
+        int i;
+        int j;
         for (i = 0; i < 56; i++) {
             permutedKey.append(originalKey.charAt(PC1[i] - 1));
         }
         String[] subKeys = new String[16];
         String initialPermutedKey = permutedKey.toString();
-        String C0 = initialPermutedKey.substring(0, 28), D0 = initialPermutedKey.substring(28);
+        String C0 = initialPermutedKey.substring(0, 28);
+        String D0 = initialPermutedKey.substring(28);
 
         // We will now operate on the left and right halves of the permutedKey
         for (i = 0; i < 16; i++) {
@@ -105,7 +107,8 @@ private String[] getSubkeys(String originalKey) {
     }
 
     private String XOR(String a, String b) {
-        int i, l = a.length();
+        int i;
+        int l = a.length();
         StringBuilder xor = new StringBuilder();
         for (i = 0; i < l; i++) {
             int firstBit = a.charAt(i) - 48; // 48 is '0' in ascii
@@ -116,7 +119,8 @@ private String XOR(String a, String b) {
     }
 
     private String createPaddedString(String s, int desiredLength, char pad) {
-        int i, l = s.length();
+        int i;
+        int l = s.length();
         StringBuilder paddedString = new StringBuilder();
         int diff = desiredLength - l;
         for (i = 0; i < diff; i++) {
@@ -165,7 +169,8 @@ private String encryptBlock(String message, String[] keys) {
         for (i = 0; i < 64; i++) {
             permutedMessage.append(message.charAt(IP[i] - 1));
         }
-        String L0 = permutedMessage.substring(0, 32), R0 = permutedMessage.substring(32);
+        String L0 = permutedMessage.substring(0, 32);
+        String R0 = permutedMessage.substring(32);
 
         // Iterate 16 times
         for (i = 0; i < 16; i++) {
@@ -198,7 +203,9 @@ private String decryptBlock(String message, String[] keys) {
      */
     public String encrypt(String message) {
         StringBuilder encryptedMessage = new StringBuilder();
-        int l = message.length(), i, j;
+        int l = message.length();
+        int i;
+        int j;
         if (l % 8 != 0) {
             int desiredLength = (l / 8 + 1) * 8;
             l = desiredLength;
@@ -223,7 +230,9 @@ public String encrypt(String message) {
      */
     public String decrypt(String message) {
         StringBuilder decryptedMessage = new StringBuilder();
-        int l = message.length(), i, j;
+        int l = message.length();
+        int i;
+        int j;
         if (l % 64 != 0) {
             throw new IllegalArgumentException("Encrypted message should be a multiple of 64 characters in length");
         }

src/main/java/com/thealgorithms/ciphers/HillCipher.java

@@ -48,7 +48,8 @@ static void encrypt(String message) {
                 System.out.println(messageVector[i][0]);
                 j++;
             }
-            int x, i;
+            int x;
+            int i;
             for (i = 0; i < matrixSize; i++) {
                 cipherMatrix[i][0] = 0;
 
@@ -96,7 +97,8 @@ static void decrypt(String message) {
                 System.out.println(messageVector[i][0]);
                 j++;
             }
-            int x, i;
+            int x;
+            int i;
             for (i = 0; i < n; i++) {
                 plainMatrix[i][0] = 0;
 
@@ -115,7 +117,10 @@ static void decrypt(String message) {
 
     // Determinant calculator
     public static int determinant(int[][] a, int n) {
-        int det = 0, sign = 1, p = 0, q = 0;
+        int det = 0;
+        int sign = 1;
+        int p = 0;
+        int q = 0;
 
         if (n == 1) {
             det = a[0][0];

src/main/java/com/thealgorithms/conversions/AnyBaseToAnyBase.java

@@ -27,7 +27,8 @@ private AnyBaseToAnyBase() {
     public static void main(String[] args) {
         Scanner in = new Scanner(System.in);
         String n;
-        int b1, b2;
+        int b1;
+        int b2;
         while (true) {
             try {
                 System.out.print("Enter number: ");
@@ -132,7 +133,8 @@ public static String base2base(String n, int b1, int b2) {
         // Declare variables: decimal value of n,
         // character of base b1, character of base b2,
         // and the string that will be returned.
-        int decimalValue = 0, charB2;
+        int decimalValue = 0;
+        int charB2;
         char charB1;
         String output = "";
         // Go through every character of n

src/main/java/com/thealgorithms/conversions/AnytoAny.java

@@ -15,7 +15,9 @@ public static void main(String[] args) {
         int sn = scn.nextInt();
         int sb = scn.nextInt();
         int db = scn.nextInt();
-        int m = 1, dec = 0, dn = 0;
+        int m = 1;
+        int dec = 0;
+        int dn = 0;
         while (sn != 0) {
             dec = dec + (sn % 10) * m;
             m *= sb;

src/main/java/com/thealgorithms/conversions/BinaryToDecimal.java

@@ -10,7 +10,10 @@ private BinaryToDecimal() {
     }
 
     public static long binaryToDecimal(long binNum) {
-        long binCopy, d, s = 0, power = 0;
+        long binCopy;
+        long d;
+        long s = 0;
+        long power = 0;
         binCopy = binNum;
         while (binCopy != 0) {
             d = binCopy % 10;

src/main/java/com/thealgorithms/conversions/BinaryToOctal.java

@@ -32,7 +32,8 @@ public static void main(String[] args) {
      */
     public static String convertBinaryToOctal(int binary) {
         String octal = "";
-        int currBit = 0, j = 1;
+        int currBit = 0;
+        int j = 1;
         while (binary != 0) {
             int code3 = 0;
             for (int i = 0; i < 3; i++) {

src/main/java/com/thealgorithms/conversions/DecimalToBinary.java

@@ -24,7 +24,10 @@ public static void main(String[] args) {
      * conventional algorithm.
      */
     public static void conventionalConversion() {
-        int n, b = 0, c = 0, d;
+        int n;
+        int b = 0;
+        int c = 0;
+        int d;
         Scanner input = new Scanner(System.in);
         System.out.printf("Conventional conversion.%n Enter the decimal number: ");
         n = input.nextInt();
@@ -42,7 +45,10 @@ public static void conventionalConversion() {
      * algorithm
      */
     public static void bitwiseConversion() {
-        int n, b = 0, c = 0, d;
+        int n;
+        int b = 0;
+        int c = 0;
+        int d;
         Scanner input = new Scanner(System.in);
         System.out.printf("Bitwise conversion.%n Enter the decimal number: ");
         n = input.nextInt();