Update DIRECTORY.md

Author: DenizAltunkapan

DIRECTORY.md

@@ -133,6 +133,7 @@
           - 📄 [PhoneticAlphabetConverter](src/main/java/com/thealgorithms/conversions/PhoneticAlphabetConverter.java)
           - 📄 [RgbHsvConversion](src/main/java/com/thealgorithms/conversions/RgbHsvConversion.java)
           - 📄 [RomanToInteger](src/main/java/com/thealgorithms/conversions/RomanToInteger.java)
+          - 📄 [TemperatureConverter](src/main/java/com/thealgorithms/conversions/TemperatureConverter.java)
           - 📄 [TimeConverter](src/main/java/com/thealgorithms/conversions/TimeConverter.java)
           - 📄 [TurkishToLatinConversion](src/main/java/com/thealgorithms/conversions/TurkishToLatinConversion.java)
           - 📄 [UnitConversions](src/main/java/com/thealgorithms/conversions/UnitConversions.java)
@@ -507,6 +508,7 @@
           - 📄 [PiNilakantha](src/main/java/com/thealgorithms/maths/PiNilakantha.java)
           - 📄 [PollardRho](src/main/java/com/thealgorithms/maths/PollardRho.java)
           - 📄 [Pow](src/main/java/com/thealgorithms/maths/Pow.java)
+          - 📄 [PowerOfFour](src/main/java/com/thealgorithms/maths/PowerOfFour.java)
           - 📄 [PowerOfTwoOrNot](src/main/java/com/thealgorithms/maths/PowerOfTwoOrNot.java)
           - 📄 [PowerUsingRecursion](src/main/java/com/thealgorithms/maths/PowerUsingRecursion.java)
           - 📁 **Prime**
@@ -525,6 +527,7 @@
           - 📄 [SieveOfAtkin](src/main/java/com/thealgorithms/maths/SieveOfAtkin.java)
           - 📄 [SieveOfEratosthenes](src/main/java/com/thealgorithms/maths/SieveOfEratosthenes.java)
           - 📄 [SimpsonIntegration](src/main/java/com/thealgorithms/maths/SimpsonIntegration.java)
+          - 📄 [SmithNumber](src/main/java/com/thealgorithms/maths/SmithNumber.java)
           - 📄 [SolovayStrassenPrimalityTest](src/main/java/com/thealgorithms/maths/SolovayStrassenPrimalityTest.java)
           - 📄 [SquareRootWithBabylonianMethod](src/main/java/com/thealgorithms/maths/SquareRootWithBabylonianMethod.java)
           - 📄 [SquareRootWithNewtonRaphsonMethod](src/main/java/com/thealgorithms/maths/SquareRootWithNewtonRaphsonMethod.java)
@@ -944,6 +947,7 @@
           - 📄 [OctalToHexadecimalTest](src/test/java/com/thealgorithms/conversions/OctalToHexadecimalTest.java)
           - 📄 [PhoneticAlphabetConverterTest](src/test/java/com/thealgorithms/conversions/PhoneticAlphabetConverterTest.java)
           - 📄 [RomanToIntegerTest](src/test/java/com/thealgorithms/conversions/RomanToIntegerTest.java)
+          - 📄 [TemperatureConverterTest](src/test/java/com/thealgorithms/conversions/TemperatureConverterTest.java)
           - 📄 [TimeConverterTest](src/test/java/com/thealgorithms/conversions/TimeConverterTest.java)
           - 📄 [TurkishToLatinConversionTest](src/test/java/com/thealgorithms/conversions/TurkishToLatinConversionTest.java)
           - 📄 [UnitConversionsTest](src/test/java/com/thealgorithms/conversions/UnitConversionsTest.java)
@@ -1279,6 +1283,7 @@
           - 📄 [PiApproximationTest](src/test/java/com/thealgorithms/maths/PiApproximationTest.java)
           - 📄 [PollardRhoTest](src/test/java/com/thealgorithms/maths/PollardRhoTest.java)
           - 📄 [PowTest](src/test/java/com/thealgorithms/maths/PowTest.java)
+          - 📄 [PowerOfFourTest](src/test/java/com/thealgorithms/maths/PowerOfFourTest.java)
           - 📄 [PowerOfTwoOrNotTest](src/test/java/com/thealgorithms/maths/PowerOfTwoOrNotTest.java)
           - 📄 [PowerUsingRecursionTest](src/test/java/com/thealgorithms/maths/PowerUsingRecursionTest.java)
           - 📄 [PronicNumberTest](src/test/java/com/thealgorithms/maths/PronicNumberTest.java)
@@ -1288,6 +1293,7 @@
           - 📄 [SecondMinMaxTest](src/test/java/com/thealgorithms/maths/SecondMinMaxTest.java)
           - 📄 [SieveOfAtkinTest](src/test/java/com/thealgorithms/maths/SieveOfAtkinTest.java)
           - 📄 [SieveOfEratosthenesTest](src/test/java/com/thealgorithms/maths/SieveOfEratosthenesTest.java)
+          - 📄 [SmithNumberTest](src/test/java/com/thealgorithms/maths/SmithNumberTest.java)
           - 📄 [SolovayStrassenPrimalityTestTest](src/test/java/com/thealgorithms/maths/SolovayStrassenPrimalityTestTest.java)
           - 📄 [SquareFreeIntegerTest](src/test/java/com/thealgorithms/maths/SquareFreeIntegerTest.java)
           - 📄 [SquareRootWithNewtonRaphsonTestMethod](src/test/java/com/thealgorithms/maths/SquareRootWithNewtonRaphsonTestMethod.java)