From ab0477a4b29115a18229c33b5532edb99b7abf5c Mon Sep 17 00:00:00 2001
From: Sumeet Gajbhar <sumit.sg34@gmail.com>
Date: Tue, 6 Aug 2019 01:55:25 +0530
Subject: [PATCH] BAEL-3127 Binary Numbers in Java (#7469)

* BAEL-3027 binary number arithmetic operations

* BAEL-3127 updated the unit test case names

* added unit test cases for built-in java functions

* updated function name

* BAEL-3127 updated unit test case names

* BAEL-3127 removed comments from code

* BAEL-3127 updated variable names

* BAEL-3027 binary number arithmetic operations

* merging upsteam

* fixing build issue

* updated formatting

* update variable names
---
 .../baeldung/binarynumbers/BinaryNumbers.java | 288 +++++++++---------
 1 file changed, 140 insertions(+), 148 deletions(-)

diff --git a/java-numbers-2/src/main/java/com/baeldung/binarynumbers/BinaryNumbers.java b/java-numbers-2/src/main/java/com/baeldung/binarynumbers/BinaryNumbers.java
index effdee07ad..62cead726f 100644
--- a/java-numbers-2/src/main/java/com/baeldung/binarynumbers/BinaryNumbers.java
+++ b/java-numbers-2/src/main/java/com/baeldung/binarynumbers/BinaryNumbers.java
@@ -1,148 +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();
-
-        while (decimalNumber > 0) {
-
-            int remainder = decimalNumber % 2;
-            int result = decimalNumber / 2;
-
-            binaryNumber.append(remainder);
-            decimalNumber = result;
-        }
-
-        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 result = 0;
-        Integer base = 1;
-
-        while (binaryNumber > 0) {
-
-            int lastDigit = binaryNumber % 10;
-            binaryNumber = binaryNumber / 10;
-
-            result += lastDigit * base;
-
-            base = base * 2;
-        }
-        return result;
-    }
-
-    /**
-     * 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());
-    }
-
-}
+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());
+    }
+
+}
\ No newline at end of file