Add missing octal conversions (TheAlgorithms#931)

Author: NithinU2802

DIRECTORY.md

@@ -50,13 +50,17 @@
   * Conversions
     * [Binary To Decimal](https://github.com/TheAlgorithms/Rust/blob/master/src/conversions/binary_to_decimal.rs)
     * [Binary To Hexadecimal](https://github.com/TheAlgorithms/Rust/blob/master/src/conversions/binary_to_hexadecimal.rs)
+    * [Binary To Octal](https://github.com/TheAlgorithms/Rust/blob/master/src/conversions/binary_to_octal.rs)
     * [Decimal To Binary](https://github.com/TheAlgorithms/Rust/blob/master/src/conversions/decimal_to_binary.rs)
     * [Decimal To Hexadecimal](https://github.com/TheAlgorithms/Rust/blob/master/src/conversions/decimal_to_hexadecimal.rs)
+    * [Decimal To Octal](https://github.com/TheAlgorithms/Rust/blob/master/src/conversions/decimal_to_octal.rs)
     * [Hexadecimal To Binary](https://github.com/TheAlgorithms/Rust/blob/master/src/conversions/hexadecimal_to_binary.rs)
     * [Hexadecimal To Decimal](https://github.com/TheAlgorithms/Rust/blob/master/src/conversions/hexadecimal_to_decimal.rs)
+    * [Hexadecimal To Octal](https://github.com/TheAlgorithms/Rust/blob/master/src/conversions/hexadecimal_to_octal.rs)
     * [Length Conversion](https://github.com/TheAlgorithms/Rust/blob/master/src/conversions/length_conversion.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)
+    * [Octal To Hexadecimal](https://github.com/TheAlgorithms/Rust/blob/master/src/conversions/octal_to_hexadecimal.rs)
     * [Rgb Cmyk Conversion](https://github.com/TheAlgorithms/Rust/blob/master/src/conversions/rgb_cmyk_conversion.rs)
   * Data Structures
     * [Avl Tree](https://github.com/TheAlgorithms/Rust/blob/master/src/data_structures/avl_tree.rs)

src/conversions/binary_to_octal.rs

@@ -0,0 +1,51 @@
+// Author: NithinU2802
+// Binary to Octal Converter: Converts Binary to Octal
+// Wikipedia References:
+// 1. https://en.wikipedia.org/wiki/Binary_number
+// 2. https://en.wikipedia.org/wiki/Octal
+
+pub fn binary_to_octal(binary_str: &str) -> Result<String, &'static str> {
+    // Validate input
+    let binary_str = binary_str.trim();
+    if binary_str.is_empty() {
+        return Err("Empty string");
+    }
+
+    if !binary_str.chars().all(|c| c == '0' || c == '1') {
+        return Err("Invalid binary string");
+    }
+
+    // Pad the binary string with zeros to make its length a multiple of 3
+    let padding_length = (3 - (binary_str.len() % 3)) % 3;
+    let padded_binary = "0".repeat(padding_length) + binary_str;
+
+    // Convert every 3 binary digits to one octal digit
+    let mut octal = String::new();
+    for chunk in padded_binary.chars().collect::<Vec<char>>().chunks(3) {
+        let binary_group: String = chunk.iter().collect();
+        let decimal = u8::from_str_radix(&binary_group, 2).map_err(|_| "Conversion error")?;
+        octal.push_str(&decimal.to_string());
+    }
+
+    Ok(octal)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_binary_to_octal() {
+        assert_eq!(binary_to_octal("1010"), Ok("12".to_string()));
+        assert_eq!(binary_to_octal("1111"), Ok("17".to_string()));
+        assert_eq!(binary_to_octal("11111111"), Ok("377".to_string()));
+        assert_eq!(binary_to_octal("1100100"), Ok("144".to_string()));
+    }
+
+    #[test]
+    fn test_invalid_input() {
+        assert_eq!(binary_to_octal(""), Err("Empty string"));
+        assert_eq!(binary_to_octal("12"), Err("Invalid binary string"));
+        assert_eq!(binary_to_octal("abc"), Err("Invalid binary string"));
+    }
+}

src/conversions/decimal_to_octal.rs

@@ -0,0 +1,37 @@
+// Author: NithinU2802
+// Decimal to Octal Converter: Converts Decimal to Octal
+// Wikipedia References:
+// 1. https://en.wikipedia.org/wiki/Decimal
+// 2. https://en.wikipedia.org/wiki/Octal
+
+pub fn decimal_to_octal(decimal_num: u64) -> String {
+    if decimal_num == 0 {
+        return "0".to_string();
+    }
+
+    let mut num = decimal_num;
+    let mut octal = String::new();
+
+    while num > 0 {
+        let remainder = num % 8;
+        octal.push_str(&remainder.to_string());
+        num /= 8;
+    }
+
+    // Reverse the string to get the correct octal representation
+    octal.chars().rev().collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_decimal_to_octal() {
+        assert_eq!(decimal_to_octal(8), "10");
+        assert_eq!(decimal_to_octal(15), "17");
+        assert_eq!(decimal_to_octal(255), "377");
+        assert_eq!(decimal_to_octal(100), "144");
+        assert_eq!(decimal_to_octal(0), "0");
+    }
+}

src/conversions/hexadecimal_to_octal.rs

@@ -0,0 +1,64 @@
+// Author: NithinU2802
+// Hexadecimal to Octal Converter: Converts Hexadecimal to Octal
+// Wikipedia References:
+// 1. https://en.wikipedia.org/wiki/Hexadecimal
+// 2. https://en.wikipedia.org/wiki/Octal
+
+pub fn hexadecimal_to_octal(hex_str: &str) -> Result<String, &'static str> {
+    let hex_str = hex_str.trim();
+
+    if hex_str.is_empty() {
+        return Err("Empty string");
+    }
+
+    // Validate hexadecimal string
+    if !hex_str.chars().all(|c| c.is_ascii_hexdigit()) {
+        return Err("Invalid hexadecimal string");
+    }
+
+    // Convert hex to decimal first
+    let decimal = u64::from_str_radix(hex_str, 16).map_err(|_| "Conversion error")?;
+
+    // Then convert decimal to octal
+    if decimal == 0 {
+        return Ok("0".to_string());
+    }
+
+    let mut num = decimal;
+    let mut octal = String::new();
+
+    while num > 0 {
+        let remainder = num % 8;
+        octal.push_str(&remainder.to_string());
+        num /= 8;
+    }
+
+    // Reverse the string to get the correct octal representation
+    Ok(octal.chars().rev().collect())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_hexadecimal_to_octal() {
+        assert_eq!(hexadecimal_to_octal("A"), Ok("12".to_string()));
+        assert_eq!(hexadecimal_to_octal("FF"), Ok("377".to_string()));
+        assert_eq!(hexadecimal_to_octal("64"), Ok("144".to_string()));
+        assert_eq!(hexadecimal_to_octal("0"), Ok("0".to_string()));
+    }
+
+    #[test]
+    fn test_invalid_input() {
+        assert_eq!(hexadecimal_to_octal(""), Err("Empty string"));
+        assert_eq!(
+            hexadecimal_to_octal("GG"),
+            Err("Invalid hexadecimal string")
+        );
+        assert_eq!(
+            hexadecimal_to_octal("XYZ"),
+            Err("Invalid hexadecimal string")
+        );
+    }
+}

src/conversions/mod.rs

@@ -1,20 +1,28 @@
 mod binary_to_decimal;
 mod binary_to_hexadecimal;
+mod binary_to_octal;
 mod decimal_to_binary;
 mod decimal_to_hexadecimal;
+mod decimal_to_octal;
 mod hexadecimal_to_binary;
 mod hexadecimal_to_decimal;
+mod hexadecimal_to_octal;
 mod length_conversion;
 mod octal_to_binary;
 mod octal_to_decimal;
+mod octal_to_hexadecimal;
 mod rgb_cmyk_conversion;
 pub use self::binary_to_decimal::binary_to_decimal;
 pub use self::binary_to_hexadecimal::binary_to_hexadecimal;
+pub use self::binary_to_octal::binary_to_octal;
 pub use self::decimal_to_binary::decimal_to_binary;
 pub use self::decimal_to_hexadecimal::decimal_to_hexadecimal;
+pub use self::decimal_to_octal::decimal_to_octal;
 pub use self::hexadecimal_to_binary::hexadecimal_to_binary;
 pub use self::hexadecimal_to_decimal::hexadecimal_to_decimal;
+pub use self::hexadecimal_to_octal::hexadecimal_to_octal;
 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;
+pub use self::octal_to_hexadecimal::octal_to_hexadecimal;
 pub use self::rgb_cmyk_conversion::rgb_to_cmyk;

src/conversions/octal_to_hexadecimal.rs

@@ -0,0 +1,50 @@
+// Author: NithinU2802
+// Octal to Hexadecimal Converter: Converts Octal to Hexadecimal
+// Wikipedia References:
+// 1. https://en.wikipedia.org/wiki/Octal
+// 2. https://en.wikipedia.org/wiki/Hexadecimal
+
+pub fn octal_to_hexadecimal(octal_str: &str) -> Result<String, &'static str> {
+    let octal_str = octal_str.trim();
+
+    if octal_str.is_empty() {
+        return Err("Empty string");
+    }
+
+    // Validate octal string
+    if !octal_str.chars().all(|c| ('0'..='7').contains(&c)) {
+        return Err("Invalid octal string");
+    }
+
+    // Convert octal to decimal first
+    let decimal = u64::from_str_radix(octal_str, 8).map_err(|_| "Conversion error")?;
+
+    // Special case for zero
+    if decimal == 0 {
+        return Ok("0".to_string());
+    }
+
+    // Convert decimal to hexadecimal
+    Ok(format!("{decimal:X}"))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_octal_to_hexadecimal() {
+        assert_eq!(octal_to_hexadecimal("12"), Ok("A".to_string()));
+        assert_eq!(octal_to_hexadecimal("377"), Ok("FF".to_string()));
+        assert_eq!(octal_to_hexadecimal("144"), Ok("64".to_string()));
+        assert_eq!(octal_to_hexadecimal("0"), Ok("0".to_string()));
+    }
+
+    #[test]
+    fn test_invalid_input() {
+        assert_eq!(octal_to_hexadecimal(""), Err("Empty string"));
+        assert_eq!(octal_to_hexadecimal("8"), Err("Invalid octal string"));
+        assert_eq!(octal_to_hexadecimal("9"), Err("Invalid octal string"));
+        assert_eq!(octal_to_hexadecimal("ABC"), Err("Invalid octal string"));
+    }
+}