diff --git a/DIRECTORY.md b/DIRECTORY.md index 3662a8cda5c2..0b282d8fb747 100644 --- a/DIRECTORY.md +++ b/DIRECTORY.md @@ -68,6 +68,7 @@ * [HexaDecimalToBinary](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/HexaDecimalToBinary.java) * [HexaDecimalToDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/HexaDecimalToDecimal.java) * [HexToOct](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/HexToOct.java) + * [IntegerToEnglish] (https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java) * [IntegerToRoman](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/IntegerToRoman.java) * [OctalToBinary](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToBinary.java) * [OctalToDecimal](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/conversions/OctalToDecimal.java) diff --git a/src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java b/src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java new file mode 100644 index 000000000000..d3b938bf492d --- /dev/null +++ b/src/main/java/com/thealgorithms/conversions/IntegerToEnglish.java @@ -0,0 +1,80 @@ +package com.thealgorithms.conversions; + +import java.util.Map; + +public final class IntegerToEnglish { + private static final Map BASE_NUMBERS_MAP = Map.ofEntries(Map.entry(0, ""), Map.entry(1, "One"), Map.entry(2, "Two"), Map.entry(3, "Three"), Map.entry(4, "Four"), Map.entry(5, "Five"), Map.entry(6, "Six"), Map.entry(7, "Seven"), Map.entry(8, "Eight"), Map.entry(9, "Nine"), + Map.entry(10, "Ten"), Map.entry(11, "Eleven"), Map.entry(12, "Twelve"), Map.entry(13, "Thirteen"), Map.entry(14, "Fourteen"), Map.entry(15, "Fifteen"), Map.entry(16, "Sixteen"), Map.entry(17, "Seventeen"), Map.entry(18, "Eighteen"), Map.entry(19, "Nineteen"), Map.entry(20, "Twenty"), + Map.entry(30, "Thirty"), Map.entry(40, "Forty"), Map.entry(50, "Fifty"), Map.entry(60, "Sixty"), Map.entry(70, "Seventy"), Map.entry(80, "Eighty"), Map.entry(90, "Ninety"), Map.entry(100, "Hundred")); + + private static final Map THOUSAND_POWER_MAP = Map.ofEntries(Map.entry(1, "Thousand"), Map.entry(2, "Million"), Map.entry(3, "Billion")); + + private IntegerToEnglish() { + } + + /** + converts numbers < 1000 to english words + */ + private static String convertToWords(int number) { + int remainder = number % 100; + + String result; + + if (remainder <= 20) { + result = BASE_NUMBERS_MAP.get(remainder); + } else if (BASE_NUMBERS_MAP.containsKey(remainder)) { + result = BASE_NUMBERS_MAP.get(remainder); + } else { + int tensDigit = remainder / 10; + int onesDigit = remainder % 10; + + result = String.format("%s %s", BASE_NUMBERS_MAP.get(tensDigit * 10), BASE_NUMBERS_MAP.get(onesDigit)); + } + + int hundredsDigit = number / 100; + + if (hundredsDigit > 0) { + result = String.format("%s %s%s", BASE_NUMBERS_MAP.get(hundredsDigit), BASE_NUMBERS_MAP.get(100), result.isEmpty() ? "" : " " + result); + } + + return result; + } + + /** + Only convert groups of three digit if they are non-zero + */ + public static String integerToEnglishWords(int number) { + if (number == 0) { + return "Zero"; + } + + StringBuilder result = new StringBuilder(); + + int index = 0; + + while (number > 0) { + int remainder = number % 1000; + number /= 1000; + + if (remainder > 0) { + String subResult = convertToWords(remainder); + + if (!subResult.isEmpty()) { + if (!result.isEmpty()) { + result.insert(0, subResult + " " + THOUSAND_POWER_MAP.get(index) + " "); + } else { + if (index > 0) { + result = new StringBuilder(subResult + " " + THOUSAND_POWER_MAP.get(index)); + } else { + result = new StringBuilder(subResult); + } + } + } + } + + index++; + } + + return result.toString(); + } +} diff --git a/src/test/java/com/thealgorithms/conversions/IntegerToEnglishTest.java b/src/test/java/com/thealgorithms/conversions/IntegerToEnglishTest.java new file mode 100644 index 000000000000..49c43402aeca --- /dev/null +++ b/src/test/java/com/thealgorithms/conversions/IntegerToEnglishTest.java @@ -0,0 +1,15 @@ +package com.thealgorithms.conversions; + +import static org.junit.jupiter.api.Assertions.assertEquals; + +import org.junit.jupiter.api.Test; + +public class IntegerToEnglishTest { + + @Test + public void testIntegerToEnglish() { + assertEquals("Two Billion One Hundred Forty Seven Million Four Hundred Eighty Three Thousand Six Hundred Forty Seven", IntegerToEnglish.integerToEnglishWords(2147483647)); + assertEquals("One Million Two Hundred Thirty Four Thousand Five Hundred Sixty Seven", IntegerToEnglish.integerToEnglishWords(1234567)); + assertEquals("Twelve Thousand Three Hundred Forty Five", IntegerToEnglish.integerToEnglishWords(12345)); + } +}