From ecf8bd76cc7232e6d1a23cc16a651fea7abeb435 Mon Sep 17 00:00:00 2001 From: Sumeet Gajbhar Date: Wed, 31 Jul 2019 01:42:25 +0530 Subject: [PATCH] BAEL-3027 binary number arithmetic operations (#7437) * 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 --- .../baeldung/binarynumbers/BinaryNumbers.java | 148 ++++++++++++++++++ .../binarynumbers/BinaryNumbersUnitTest.java | 73 +++++++++ 2 files changed, 221 insertions(+) create mode 100644 java-numbers-2/src/main/java/com/baeldung/binarynumbers/BinaryNumbers.java create mode 100644 java-numbers-2/src/test/java/com/baeldung/binarynumbers/BinaryNumbersUnitTest.java 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 new file mode 100644 index 0000000000..effdee07ad --- /dev/null +++ b/java-numbers-2/src/main/java/com/baeldung/binarynumbers/BinaryNumbers.java @@ -0,0 +1,148 @@ +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()); + } + +} diff --git a/java-numbers-2/src/test/java/com/baeldung/binarynumbers/BinaryNumbersUnitTest.java b/java-numbers-2/src/test/java/com/baeldung/binarynumbers/BinaryNumbersUnitTest.java new file mode 100644 index 0000000000..ca6022261d --- /dev/null +++ b/java-numbers-2/src/test/java/com/baeldung/binarynumbers/BinaryNumbersUnitTest.java @@ -0,0 +1,73 @@ +package com.baeldung.binarynumbers; + +import static org.junit.Assert.assertEquals; + +import org.junit.Test; + +public class BinaryNumbersUnitTest { + + private BinaryNumbers binaryNumbers = new BinaryNumbers(); + + @Test + public void given_decimalNumber_then_returnBinaryNumber() { + assertEquals(Integer.valueOf(1000), binaryNumbers.convertDecimalToBinary(8)); + assertEquals(Integer.valueOf(10100), binaryNumbers.convertDecimalToBinary(20)); + } + + @Test + public void given_decimalNumber_then_convertToBinaryNumber() { + assertEquals("1000", Integer.toBinaryString(8)); + assertEquals("10100", Integer.toBinaryString(20)); + } + + @Test + public void given_binaryNumber_then_ConvertToDecimalNumber() { + assertEquals(8, Integer.parseInt("1000", 2)); + assertEquals(20, Integer.parseInt("10100", 2)); + } + + @Test + public void given_binaryNumber_then_returnDecimalNumber() { + assertEquals(Integer.valueOf(8), binaryNumbers.convertBinaryToDecimal(1000)); + assertEquals(Integer.valueOf(20), binaryNumbers.convertBinaryToDecimal(10100)); + } + + @Test + public void given_twoBinaryNumber_then_returnAddition() { + // adding 4 and 10 + assertEquals(Integer.valueOf(1110), binaryNumbers.addBinaryNumber(100, 1010)); + + // adding 26 and 14 + assertEquals(Integer.valueOf(101000), binaryNumbers.addBinaryNumber(11010, 1110)); + } + + @Test + public void given_twoBinaryNumber_then_returnSubtraction() { + // subtracting 16 from 25 + assertEquals(Integer.valueOf(1001), binaryNumbers.substractBinaryNumber(11001, 10000)); + + // subtracting 29 from 16, the output here is negative + assertEquals(Integer.valueOf(1101), binaryNumbers.substractBinaryNumber(10000, 11101)); + } + + @Test + public void given_binaryLiteral_thenReturnDecimalValue() { + + byte five = 0b101; + assertEquals((byte) 5, five); + + short three = 0b11; + assertEquals((short) 3, three); + + int nine = 0B1001; + assertEquals(9, nine); + + long twentyNine = 0B11101; + assertEquals(29, twentyNine); + + int minusThirtySeven = -0B100101; + assertEquals(-37, minusThirtySeven); + + } + +}