Started Rust in Action MEAP.

1 files changed, 43 insertions, 0 deletions

diff --git a/rust-book/ftoctof/src/main.rs b/rust-book/ftoctof/src/main.rs
new file mode 100755
index 0000000..6425344
--- /dev/null
+++ b/rust-book/ftoctof/src/main.rs
@@ -0,0 +1,43 @@
+use std::env;
+
+fn print_usage() {
+    eprintln!("error: usage: ftoctof [degrees] [f|c]");
+}
+
+fn main() {
+    // grab degrees value
+    let degrees: f32 = match env::args().nth(1) {
+        Some(s) => {
+            let attempt: f32 = s.trim().parse()
+                .expect("error: could not parse degrees");
+            attempt
+        },
+        None => {
+            print_usage();
+            return;
+        },
+    };
+
+    // grab scale identifier
+    let scale = match env::args().nth(2) {
+        Some(s) => s.to_lowercase(),
+        None => {
+            print_usage();
+            return;
+        },
+    };
+
+    // compute and print conversion
+    if scale == "f" {
+        let result: f32 = (degrees - 32.0) * 5.0 / 9.0;
+        println!("{} degrees fahrenheight is {} degrees celcius.", degrees, result);
+    }
+    else if scale == "c" {
+        let result: f32 = degrees * 9.0 / 5.0 + 32.0;
+        println!("{} degrees celcius is {} degrees fahrenheight.", degrees, result);
+    }
+    else {
+        print_usage();
+    }
+
+}