arg parsing

src/cmd.rs

@@ -0,0 +1,35 @@
+use std::{collections::HashMap, process::exit};
+
+pub fn help() {
+    println!(
+        "usage:
+airport-paths <aiport code> <airport code>
+    finds the shortest path between the first and second airport-paths
+airport-paths -h
+    shows this help"
+    );
+}
+
+pub fn handle_args(args: Vec<String>, _code_to_id: HashMap<String, usize>) -> (usize, usize) {
+    let (origin, destination) = match args.len() {
+        3 => {
+            let exit_handler = || {
+                println!("unable to find airport");
+                exit(2);
+            };
+            let origin = _code_to_id.get(&args[1]).unwrap_or_else(exit_handler);
+            let destination = _code_to_id.get(&args[2]).unwrap_or_else(exit_handler);
+
+            (origin, destination)
+        }
+        _ => {
+            help();
+            match args.get(1).map(String::as_str) {
+                Some("-h") => exit(0),
+                _ => exit(2),
+            }
+        }
+    };
+
+    (*origin, *destination)
+}

src/main.rs

@@ -1,12 +1,14 @@
 #![allow(dead_code)]
 
 mod airport;
+mod cmd;
 mod distance;
 mod parse;
 
 use std::{
     cell::RefCell,
     collections::{hash_map::Entry, HashMap},
+    env,
     rc::Rc,
 };
 
@@ -128,5 +130,9 @@ fn main() {
         };
     }
 
-    println!("{graph:#?}")
+    // Using command line arguments as input
+    let args: Vec<String> = env::args().collect();
+    let (origin_id, destination_id) = cmd::handle_args(args, _code_to_id);
+
+    println!("{:#?} {:#?}", graph[&origin_id], graph[&destination_id]);
 }