Length conversion

DIRECTORY.md

@@ -55,6 +55,7 @@
     * [Hexadecimal To Decimal](https://github.com/TheAlgorithms/Rust/blob/master/src/conversions/hexadecimal_to_decimal.rs)
     * [Octal To Binary](https://github.com/TheAlgorithms/Rust/blob/master/src/conversions/octal_to_binary.rs)
     * [Octal To Decimal](https://github.com/TheAlgorithms/Rust/blob/master/src/conversions/octal_to_decimal.rs)
+    * [Length Conversions](https://github.com/TheAlgorithms/Rust/blob/master/src/conversions/length_conversion.rs)
   * Data Structures
     * [Avl Tree](https://github.com/TheAlgorithms/Rust/blob/master/src/data_structures/avl_tree.rs)
     * [B Tree](https://github.com/TheAlgorithms/Rust/blob/master/src/data_structures/b_tree.rs)

src/conversions/length_conversion.rs

@@ -0,0 +1,107 @@
+/// Author : https://github.com/ali77gh
+/// Conversion of length units.
+///
+/// Available Units:
+/// -> Wikipedia reference: https://en.wikipedia.org/wiki/Millimeter
+/// -> Wikipedia reference: https://en.wikipedia.org/wiki/Centimeter
+/// -> Wikipedia reference: https://en.wikipedia.org/wiki/Meter
+/// -> Wikipedia reference: https://en.wikipedia.org/wiki/Kilometer
+/// -> Wikipedia reference: https://en.wikipedia.org/wiki/Inch
+/// -> Wikipedia reference: https://en.wikipedia.org/wiki/Foot
+/// -> Wikipedia reference: https://en.wikipedia.org/wiki/Yard
+/// -> Wikipedia reference: https://en.wikipedia.org/wiki/Mile
+
+/// Universal Units on Length
+pub enum LengthUnit {
+    Millimeter,
+    Centimeter,
+    Meter,
+    Kilometer,
+    Inch,
+    Foot,
+    Yard,
+    Mile,
+}
+
+/// Private methods
+/// This is a n*n problem
+/// It's gonna be 56 functions or 56 cases in match statement
+/// It's hard to write code for every unit to unit so I solve this problem
+/// by converting input to meter and than convert it to output
+impl LengthUnit {
+    /// This function give you a number (let's call it n)
+    /// So if you multiple a value in this unit to n you will get meters
+    ///
+    /// m * in-unit = meter
+    fn get_unit_to_meter_multiplier(&self) -> f64 {
+        match self {
+            LengthUnit::Millimeter => 0.001,
+            LengthUnit::Centimeter => 0.01,
+            LengthUnit::Meter => 1.0,
+            LengthUnit::Kilometer => 1000.0,
+            LengthUnit::Inch => 0.0254,
+            LengthUnit::Foot => 0.3048,
+            LengthUnit::Yard => 0.9144,
+            LengthUnit::Mile => 1609.34,
+        }
+    }
+
+    /// This function give you a number (let's call it n)
+    /// So if you multiple a value in meters to n you will get unit
+    ///
+    /// m * meter = in-unit
+    fn get_unit_from_meter_multiplier(&self) -> f64 {
+        1.0 / self.get_unit_to_meter_multiplier()
+    }
+}
+
+/// This function will convert a value in unit of [from] to value in unit of [to]
+/// by first converting it to meter and than convert it to destination unit
+pub fn length_conversion(input: f64, from: LengthUnit, to: LengthUnit) -> f64 {
+    input * from.get_unit_to_meter_multiplier() * to.get_unit_from_meter_multiplier()
+}
+
+#[cfg(test)]
+mod length_conversion_tests {
+    use super::LengthUnit::*;
+    use super::*;
+
+    #[test]
+    fn meter_to_other() {
+        assert_eq!(length_conversion(4f64, Meter, Millimeter), 4000.0);
+        assert_eq!(length_conversion(4f64, Meter, Foot), 13.123359580052492);
+        assert_eq!(length_conversion(1.0, Meter, Kilometer), 0.001);
+    }
+
+    #[test]
+    fn other_to_meter() {
+        assert_eq!(length_conversion(4f64, Millimeter, Meter), 0.004);
+        assert_eq!(length_conversion(2.0, Foot, Meter), 0.6096);
+        assert_eq!(length_conversion(1.0, Inch, Meter), 0.0254);
+        assert_eq!(length_conversion(4.0, Yard, Meter), 3.6576);
+        assert_eq!(length_conversion(3.0, Foot, Meter), 0.9144000000000001);
+    }
+
+    #[test]
+    fn other_to_other() {
+        // ---------------
+        assert_eq!(length_conversion(1.0, Kilometer, Inch), 39370.07874015748);
+        assert_eq!(length_conversion(3.0, Kilometer, Mile), 1.8641182099494205);
+        assert_eq!(length_conversion(4.0, Foot, Yard), 1.3333333333333335);
+        assert_eq!(length_conversion(2.0, Inch, Mile), 3.156573502181019e-5);
+        assert_eq!(length_conversion(2.0, Centimeter, Millimeter), 20.0);
+        assert_eq!(
+            length_conversion(2.0, Centimeter, Yard),
+            0.021872265966754158
+        );
+        assert_eq!(length_conversion(4.0, Yard, Kilometer), 0.0036576);
+        assert_eq!(length_conversion(3.0, Foot, Inch), 36.00000000000001);
+        assert_eq!(length_conversion(4.0, Mile, Kilometer), 6.43736);
+        assert_eq!(length_conversion(2.0, Mile, Inch), 126719.68503937007);
+        assert_eq!(length_conversion(3.0, Millimeter, Centimeter), 0.3);
+        assert_eq!(
+            length_conversion(3.0, Millimeter, Inch),
+            0.11811023622047245
+        );
+    }
+}

src/conversions/mod.rs

@@ -4,6 +4,7 @@ mod decimal_to_binary;
 mod decimal_to_hexadecimal;
 mod hexadecimal_to_binary;
 mod hexadecimal_to_decimal;
+mod length_conversion;
 mod octal_to_binary;
 mod octal_to_decimal;
 pub use self::binary_to_decimal::binary_to_decimal;
@@ -12,5 +13,6 @@ pub use self::decimal_to_binary::decimal_to_binary;
 pub use self::decimal_to_hexadecimal::decimal_to_hexadecimal;
 pub use self::hexadecimal_to_binary::hexadecimal_to_binary;
 pub use self::hexadecimal_to_decimal::hexadecimal_to_decimal;
+pub use self::length_conversion::length_conversion;
 pub use self::octal_to_binary::octal_to_binary;
 pub use self::octal_to_decimal::octal_to_decimal;