Add decimal to binary conversion (TheAlgorithms#465)

Author: lucioreyli

src/conversions/decimal_to_binary.rs

@@ -0,0 +1,26 @@
+pub fn decimal_to_binary(base_num: u64) -> String {
+    let mut num = base_num;
+    let mut binary_num = String::new();
+    loop {
+        let bit = (num % 2).to_string();
+        binary_num.push_str(&bit);
+        num /= 2;
+        if num == 0 {
+            break;
+        }
+    }
+
+    let bits = binary_num.chars();
+    bits.rev().collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn converting_decimal_to_binary() {
+        assert_eq!(decimal_to_binary(542), "1000011110");
+        assert_eq!(decimal_to_binary(92), "1011100");
+    }
+}

src/conversions/mod.rs

@@ -0,0 +1,3 @@
+mod decimal_to_binary;
+
+pub use self::decimal_to_binary::decimal_to_binary;

src/lib.rs

@@ -4,6 +4,7 @@ pub mod backtracking;
 pub mod big_integer;
 pub mod ciphers;
 pub mod compression;
+pub mod conversions;
 pub mod data_structures;
 pub mod dynamic_programming;
 pub mod general;