Temperature convertion

src/main/java/com/thealgorithms/conversions/TemperatureConverter.java

@@ -0,0 +1,140 @@
+package com.thealgorithms.conversions;
+
+/**
+ * Utility class for converting temperatures between Celsius, Fahrenheit, and Kelvin.
+ *
+ * <p>Formulas reference:
+ * <a href="https://en.wikipedia.org/wiki/Conversion_of_scales_of_temperature">...</a>
+ * <p>Note: Some of the formulas presented on the wikipedia page are not correct
+ *
+ * <p>Examples:
+ * <ul>
+ *   <li>0 °C = 32 °F = 273.15 K</li>
+ *   <li>-40 °C = -40 °F</li>
+ * </ul>
+ */
+public final class TemperatureConverter {
+
+    private TemperatureConverter() {
+    }
+
+    /**
+     * Converts Celsius to Fahrenheit.
+     * Formula: °C × 9/5 + 32
+     */
+    public static Double celsiusToFahrenheit(Double celsius) {
+        if (celsius < -273.15) {
+            throw new IllegalArgumentException("Temperature below absolute zero (-273.15°C).");
+        }
+        return (celsius * 1.8) + 32;
+    }
+
+    public static String celsiusToFahrenheit(String celsius) {
+        String[] temp = celsius.replace("°C", "").trim().split(" ");
+        double value = Double.parseDouble(temp[0]);
+        if (value < -273.15) {
+            throw new IllegalArgumentException("Temperature below absolute zero (-273.15°C).");
+        }
+        return ((value * 1.8) + 32) + "°F";
+    }
+
+    /**
+     * Converts Celsius to Kelvin.
+     * Formula: °C + 273.15
+     */
+    public static Double celsiusToKelvin(Double celsius) {
+        if (celsius < -273.15) {
+            throw new IllegalArgumentException("Temperature below absolute zero (-273.15°C).");
+        }
+        return celsius + 273.15;
+    }
+
+    public static String celsiusToKelvin(String celsius) {
+        String[] temp = celsius.replace("°C", "").trim().split(" ");
+        double value = Double.parseDouble(temp[0]);
+        if (value < -273.15) {
+            throw new IllegalArgumentException("Temperature below absolute zero (-273.15°C).");
+        }
+        return (value + 273.15) + " K";
+    }
+
+    /**
+     * Converts: Fahrenheit to Celsius.
+     * Formula: (°F - 32) * 5/9
+     */
+    public static Double fahrenheitToCelsius(Double fahrenheit) {
+        if (fahrenheit < -459.67) {
+            throw new IllegalArgumentException("Temperature below absolute zero (-459.67°F).");
+        }
+        return (fahrenheit - 32) * (5.0 / 9.0);
+    }
+
+    public static String fahrenheitToCelsius(String fahrenheit) {
+        String[] temp = fahrenheit.replace("°F", "").trim().split(" ");
+        double value = Double.parseDouble(temp[0]);
+        if (value < -459.67) {
+            throw new IllegalArgumentException("Temperature below absolute zero (-459.67°F).");
+        }
+        return ((value - 32) * (5.0 / 9.0)) + "°C";
+    }
+
+    /**
+     * Converts: Fahrenheit to Kelvin.
+     * Formula: (°F - 32) * 5/9 + 273.15
+     */
+    public static Double fahrenheitToKelvin(Double fahrenheit) {
+        if (fahrenheit < -459.67) {
+            throw new IllegalArgumentException("Temperature below absolute zero (-459.67°F).");
+        }
+        return (fahrenheit - 32) * (5.0 / 9.0) + 273.15;
+    }
+
+    public static String fahrenheitToKelvin(String fahrenheit) {
+        String[] temp = fahrenheit.replace("°F", "").trim().split(" ");
+        double value = Double.parseDouble(temp[0]);
+        if (value < -459.67) {
+            throw new IllegalArgumentException("Temperature below absolute zero (-459.67°F).");
+        }
+        return ((value - 32) * (5.0 / 9.0) + 273.15) + " K";
+    }
+
+    /**
+     * Converts: Kelvin to Celsius.
+     * Formula: K - 273.15
+     */
+    public static Double kelvinToCelsius(Double kelvin) {
+        if (kelvin < 0) {
+            throw new IllegalArgumentException("Temperature below absolute zero (0 K).");
+        }
+        return kelvin - 273.15;
+    }
+
+    public static String kelvinToCelsius(String kelvin) {
+        String[] temp = kelvin.replace("K", "").trim().split(" ");
+        double value = Double.parseDouble(temp[0]);
+        if (value < 0) {
+            throw new IllegalArgumentException("Temperature below absolute zero (0 K).");
+        }
+        return (value - 273.15) + "°C";
+    }
+
+    /**
+     * Converts: Kelvin to Fahrenheit.
+     * Formula: (K - 273.15) * 9/5 + 32
+     */
+    public static Double kelvinToFahrenheit(Double kelvin) {
+        if (kelvin < 0) {
+            throw new IllegalArgumentException("Temperature below absolute zero (0 K).");
+        }
+        return 1.8 * (kelvin - 273.15) + 32;
+    }
+
+    public static String kelvinToFahrenheit(String kelvin) {
+        String[] temp = kelvin.replace("K", "").trim().split(" ");
+        double value = Double.parseDouble(temp[0]);
+        if (value < 0) {
+            throw new IllegalArgumentException("Temperature below absolute zero (0 K).");
+        }
+        return (1.8 * (value - 273.15) + 32) + "°F";
+    }
+}

src/test/java/com/thealgorithms/conversions/TemperatureConverterTest.java

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+package com.thealgorithms.conversions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class TemperatureConverterTest {
+
+    @Test
+    public void testValidCelsiusToFahrenheit() {
+        assertEquals(33.8, TemperatureConverter.celsiusToFahrenheit(1.0));
+        assertEquals(34.718, TemperatureConverter.celsiusToFahrenheit(1.51));
+        assertEquals(14.0, TemperatureConverter.celsiusToFahrenheit(-10.0));
+        assertEquals("33.8°F", TemperatureConverter.celsiusToFahrenheit("1°C"));
+        assertEquals("34.718°F", TemperatureConverter.celsiusToFahrenheit("1.51°C"));
+        assertEquals("14.0°F", TemperatureConverter.celsiusToFahrenheit("-10.0°C"));
+    }
+
+    @Test
+    public void testValidCelsiusToKevin() {
+        assertEquals(274.15, TemperatureConverter.celsiusToKelvin(1.0));
+        assertEquals(274.65999999999997, TemperatureConverter.celsiusToKelvin(1.51));
+        assertEquals(263.15, TemperatureConverter.celsiusToKelvin(-10.0));
+        assertEquals("274.15 K", TemperatureConverter.celsiusToKelvin("1°C"));
+        assertEquals("274.65999999999997 K", TemperatureConverter.celsiusToKelvin("1.51°C"));
+        assertEquals("263.15 K", TemperatureConverter.celsiusToKelvin("-10.0°C"));
+    }
+
+    @Test
+    public void testValidFahrenheitToCelsius() {
+        assertEquals(-17.22222222222222, TemperatureConverter.fahrenheitToCelsius(1.0));
+        assertEquals(65.55555555555556, TemperatureConverter.fahrenheitToCelsius(150.0));
+        assertEquals(-23.333333333333336, TemperatureConverter.fahrenheitToCelsius(-10.0));
+        assertEquals("-17.22222222222222°C", TemperatureConverter.fahrenheitToCelsius("1°F"));
+        assertEquals("65.55555555555556°C", TemperatureConverter.fahrenheitToCelsius("150.0°F"));
+        assertEquals("-23.333333333333336°C", TemperatureConverter.fahrenheitToCelsius("-10.0°F"));
+    }
+
+    @Test
+    public void testValidFahrenheitToKelvin() {
+        assertEquals(255.92777777777775, TemperatureConverter.fahrenheitToKelvin(1.0));
+        assertEquals(328.7055555555555, TemperatureConverter.fahrenheitToKelvin(132.0));
+        assertEquals(249.81666666666663, TemperatureConverter.fahrenheitToKelvin(-10.0));
+        assertEquals("255.92777777777775 K", TemperatureConverter.fahrenheitToKelvin("1°F"));
+        assertEquals("328.7055555555555 K", TemperatureConverter.fahrenheitToKelvin("132°F"));
+        assertEquals("249.81666666666663 K", TemperatureConverter.fahrenheitToKelvin("-10.0°F"));
+    }
+
+    @Test
+    public void testValidKelvinToCelsius() {
+        assertEquals(-272.15, TemperatureConverter.kelvinToCelsius(1.0));
+        assertEquals(-141.14999999999998, TemperatureConverter.kelvinToCelsius(132.0));
+        assertEquals(-263.15, TemperatureConverter.kelvinToCelsius(10.0));
+        assertEquals("-272.15°C", TemperatureConverter.kelvinToCelsius("1.0 K"));
+        assertEquals("-141.14999999999998°C", TemperatureConverter.kelvinToCelsius("132.0 K"));
+        assertEquals("-263.15°C", TemperatureConverter.kelvinToCelsius("10.0 K"));
+    }
+
+    @Test
+    public void testValidKelvinToFahrenheit() {
+        assertEquals(-457.86999999999995, TemperatureConverter.kelvinToFahrenheit(1.0));
+        assertEquals(-222.06999999999996, TemperatureConverter.kelvinToFahrenheit(132.0));
+        assertEquals(-441.66999999999996, TemperatureConverter.kelvinToFahrenheit(10.0));
+        assertEquals("-457.86999999999995°F", TemperatureConverter.kelvinToFahrenheit("1.0 K"));
+        assertEquals("-222.06999999999996°F", TemperatureConverter.kelvinToFahrenheit("132.0 K"));
+        assertEquals("-441.66999999999996°F", TemperatureConverter.kelvinToFahrenheit("10.0 K"));
+    }
+
+    @Test
+    public void testAbsoluteZeroAndBelow() {
+        assertThrows(IllegalArgumentException.class, () -> TemperatureConverter.celsiusToFahrenheit(-300.0));
+        assertThrows(IllegalArgumentException.class, () -> TemperatureConverter.celsiusToKelvin("-300°C"));
+        assertThrows(IllegalArgumentException.class, () -> TemperatureConverter.fahrenheitToCelsius(-500.0));
+        assertThrows(IllegalArgumentException.class, () -> TemperatureConverter.fahrenheitToKelvin("-500°F"));
+        assertThrows(IllegalArgumentException.class, () -> TemperatureConverter.kelvinToCelsius(-1.0));
+        assertThrows(IllegalArgumentException.class, () -> TemperatureConverter.kelvinToFahrenheit("-1 K"));
+    }
+}