func to get file content as Result<String>

src/main.rs

@@ -30,6 +30,11 @@ fn parse_instruction(c: char) -> Result<Instruction, &'static str> {
     }
 }
 
-fn main() {
-    let file_data = include_str!("../two_robots.txt");
+fn open_file(filename: &str) -> io::Result<String> {
+    let content = fs::read_to_string(filename)?;
+    Ok(content)
+}
+
+fn main() {
+    let conf = open_file("two_robots.txt");
 }