lecture 02

lectures/02/io.rs

@@ -0,0 +1,38 @@
+use std::env;
+use std::fs::File;
+use std::io::{self, BufRead};
+
+fn read_lines() {
+    let mut line = String::new();
+
+    while let Ok(n) = io::stdin().read_line(&mut line) {
+        if n == 0 {
+            break;
+        }
+        print!("{line}");
+        line.clear();
+    }
+}
+
+fn lines() -> io::Result<Vec<String>> {
+    io::stdin().lines().collect()
+}
+
+fn lines2() -> Vec<String> {
+    io::stdin().lines().filter_map(|x| x.ok()).collect()
+}
+
+fn file_lines(file: &str) -> io::Result<Vec<String>> {
+    io::BufReader::new(File::open(file)?).lines().collect()
+}
+
+fn main() {
+    let args: Vec<_> = env::args().skip(1).collect();
+    println!("{args:?}");
+
+    if args.len() > 0 {
+        println!("{:?}", file_lines(&args[0]));
+    } else {
+        println!("{:?}", lines());
+    }
+}