feat(solutions): add find-closest-number/rust/function

challenges/find-closest-number/solutions/rust/function/src/main.rs

@@ -0,0 +1,46 @@
+use std::io;
+
+/// From list of `integers`, get number closest to a given `value`.
+pub fn find_closest_number(integers: &[i32], value: i32) -> i32 {
+    let mut current = integers[0];
+    for integer in integers {
+        if (integer - value).abs() < (current - value).abs() {
+            current = *integer;
+        }
+    }
+    return current.clone();
+}
+
+fn main() {
+    let mut given_number = String::new();
+    io::stdin()
+        .read_line(&mut given_number)
+        .expect("Failed to read `stdin` line.");
+    let given_number: i32 = given_number
+        .trim()
+        .parse()
+        .expect("Failed to convert `given_number` as an `i32`.");
+
+    let mut length = String::new();
+    io::stdin()
+        .read_line(&mut length)
+        .expect("Failed to read `stdin` line.");
+    let length: usize = length
+        .trim()
+        .parse()
+        .expect("Failed to convert `length` as an `usize`.");
+
+    let mut integers: Vec<i32> = Vec::new();
+    for _ in 0..length {
+        let mut integer = String::new();
+        io::stdin()
+            .read_line(&mut integer)
+            .expect("Failed to read `stdin` line.");
+        let integer: i32 = integer
+            .trim()
+            .parse()
+            .expect("Failed to convert `integer` as an `i32`.");
+        integers.push(integer);
+    }
+    println!("{}", find_closest_number(&integers, given_number));
+}