reorganized the directories

projects/nth_fibonacci/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "nth_fibonacci"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+num-format = "0.4.0"

projects/nth_fibonacci/src/main.rs

@@ -0,0 +1,47 @@
+use std::io;
+use num_format::{Locale, ToFormattedString};
+// use std::process;
+
+fn nth_fibonacci(n: u64) -> u64 {
+
+    if n == 0 || n == 1 { 
+        return n; 
+    } else { 
+        return nth_fibonacci(n - 1) + nth_fibonacci(n - 2); 
+    }
+}
+
+fn main() {
+    println! ("找出第 n 个斐波拉基数");
+
+    'main_loop: loop {
+        println! ("请输入 n: （Q/quit 退出程序）");
+
+        let n: u64 = loop {
+            let mut tmp = String::new();
+
+            io::stdin()
+                .read_line(&mut tmp)
+                .expect("读取输入失败！");
+
+            let tmp = tmp.trim();
+
+            if tmp.eq("Q") || tmp.eq("quit") { 
+                // process::exit(0); 
+                break 'main_loop;
+            }
+
+            match tmp.parse() {
+                Ok(num) => { break num },
+                Err(_) => {
+                    println! ("请输入一个正整数！\n");
+                    continue;
+                },
+            };
+        };
+
+        println! ("第 {} 个斐波拉基数为：{}", 
+            n, 
+            nth_fibonacci(n).to_formatted_string(&Locale::en));
+    }
+}