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-rwxr-xr-xrust-book/ftoctof/src/main.rs43
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();
+ }
+
+}