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BAEL-3027 binary number arithmetic operations (#7437)

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* 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
This commit is contained in:
Sumeet Gajbhar 2019-07-31 01:42:25 +05:30 committed by maibin
parent db90a53e38
commit ecf8bd76cc
2 changed files with 221 additions and 0 deletions
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148
java-numbers-2/src/main/java/com/baeldung/binarynumbers/BinaryNumbers.java Normal file
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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());
}
}

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java-numbers-2/src/test/java/com/baeldung/binarynumbers/BinaryNumbersUnitTest.java Normal file
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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);
}
}