2016 Update

Task/Caesar-cipher/Rust/caesar-cipher.rust

@@ -0,0 +1,36 @@
+use std::io::{self, Write};
+use std::fmt::Display;
+use std::{env, process};
+
+fn main() {
+    let shift: u8 = env::args().nth(1)
+        .unwrap_or_else(|| exit_err("No shift provided", 2))
+        .parse()
+        .unwrap_or_else(|e| exit_err(e, 3));
+
+    let plain = get_input()
+        .unwrap_or_else(|e| exit_err(&e, e.raw_os_error().unwrap_or(-1)));
+
+    let cipher = plain.chars()
+        .map(|c| {
+            let case = if c.is_uppercase() {'A'} else {'a'} as u8;
+            if c.is_alphabetic() { (((c as u8 - case + shift) % 26) + case) as char } else { c }
+        }).collect::<String>();
+
+    println!("Cipher text: {}", cipher.trim());
+}
+
+
+fn get_input() -> io::Result<String> {
+    print!("Plain text:  ");
+    try!(io::stdout().flush());
+
+    let mut buf = String::new();
+    try!(io::stdin().read_line(&mut buf));
+    Ok(buf)
+}
+
+fn exit_err<T: Display>(msg: T, code: i32) -> ! {
+    let _ = writeln!(&mut io::stderr(), "ERROR: {}", msg);
+    process::exit(code);
+}