add calculator

.gitignore

@@ -1 +1 @@
-/target
+target

calculator/Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "calculator"
+version = "0.1.0"

calculator/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "calculator"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

calculator/src/main.rs

@@ -0,0 +1,111 @@
+use std::io;
+
+struct Calculator {
+    first_number: i32,
+    second_number: i32,
+}
+
+impl Calculator {
+    /**
+     * 加法
+     */
+    fn add(&self) -> i32 {
+        self.first_number + self.second_number
+    }
+
+    /**
+     * 减法
+     */
+    fn sub(&self) -> i32 {
+        self.first_number - self.second_number
+    }
+
+    /**
+     * 乘法
+     */
+    fn mul(&self) -> i32 {
+        self.first_number * self.second_number
+    }
+
+    /**
+     * 除法
+     */
+    fn div(&self) -> i32 {
+        self.first_number / self.second_number
+    }
+}
+
+fn main() {
+    let mut calculator = Calculator {
+        first_number: 0,
+        second_number: 0,
+    };
+    loop {
+        println!("Please Enter Your Algorithm");
+        println!("1. add");
+        println!("2. sub");
+        println!("3. mul");
+        println!("4. div");
+        println!("5. return");
+        let mut algorithm_input = String::new();
+        io::stdin()
+            .read_line(&mut algorithm_input)
+            .expect("Failed to a line");
+        let algorithm_trim = algorithm_input.trim();
+        let algorithm: i32;
+        if let Ok(parsed_value) = algorithm_trim.parse() {
+            algorithm = parsed_value
+        } else {
+            return;
+        }
+
+        if algorithm == 5 {
+            return;
+        }
+
+        println!("Please Enter First Number");
+        let mut first_number_input = String::new();
+        io::stdin()
+            .read_line(&mut first_number_input)
+            .expect("Failed to a line");
+        let first_number_trim = first_number_input.trim();
+        let first_number: i32;
+        if let Ok(parsed_value) = first_number_trim.parse() {
+            first_number = parsed_value
+        } else {
+            return;
+        }
+
+        println!("Please Enter Second Number");
+        let mut second_number_input = String::new();
+        io::stdin()
+            .read_line(&mut second_number_input)
+            .expect("Failed to a line");
+        let second_number_trim = second_number_input.trim();
+        let second_number: i32;
+        if let Ok(parsed_value) = second_number_trim.parse() {
+            second_number = parsed_value
+        } else {
+            return;
+        }
+
+        calculator.first_number = first_number;
+        calculator.second_number = second_number;
+
+        match algorithm {
+            1 => {
+                println!("add: {}", calculator.add())
+            }
+            2 => {
+                println!("sub: {}", calculator.sub())
+            }
+            3 => {
+                println!("mul: {}", calculator.mul())
+            }
+            4 => {
+                println!("div: {}", calculator.div())
+            }
+            _ => return,
+        }
+    }
+}

main.rs

@@ -1,162 +1,58 @@
+struct Car {
+    color: String,
+    transmission: Transmission,
+    convertible: bool,
+    age: (Age, u32),
+}
+
+#[derive(PartialEq, Debug)]
+enum Age {
+    New,
+    Used,
+}
+
+#[derive(PartialEq, Debug)]
+enum Transmission {
+    Manual,
+    SemiAuto,
+    Automatic,
+}
+
+fn car_factory(color: String, transmission: Transmission, convertible: bool, miles: u32) -> Car {
+    Car {
+        color,
+        transmission,
+        convertible,
+        age: car_quality(miles),
+    }
+}
+
+fn car_quality(miles: u32) -> (Age, u32) {
+    if miles > 100 {
+        return (Age::Used, miles);
+    }
+
+    (Age::New, miles)
+}
+
 fn main() {
-    let guess: u32 = "42".parse().expect("Not a number!");
+    println!("Hello, world");
-    println!("You guessed: {}", guess);
+    let colors = ["Blue", "Green", "Red", "Silver"];
-    let heart_eyed_cat = '😻';
+    let mut car = car_factory(String::from(colors[0]), Transmission::Automatic, false, 0);
-    println!("{}", heart_eyed_cat);
-
-    let cc = another_function(3, 'a');
-    println!("The value of cc is: {}", cc);
-
-    // Statements and Expressions
-    let x = {
-        let y = 5;
-        y + 1
-    };
-    println!("The value of x is: {}", x);
-
-    for number in 1..4 {
-        println!("{}!", number);
-    }
-
-    let result = fibonacci_function(3);
-    println!("The result is: {}", result);
-    // 相互转换摄氏与华氏温度
-    let celsius = 30.0;
-    let fahrenheit = celsius_to_fahrenheit(celsius);
-    println!("{} celsius is {} fahrenheit.", celsius, fahrenheit);
-    let fahrenheit = 86.0;
-    let celsius = fahrenheit_to_celsius(fahrenheit);
-    println!("{} fahrenheit is {} celsius.", fahrenheit, celsius);
-
-    let mut s = String::from("hello");
-    s.push_str(", world!");
-    println!("{}", s);
-
-    let s2 = s;
-    println!("{}", s2);
-    // println!("{}", s);
-
-    let t = String::from("hello");
-    takes_ownership(t);
-    // println!("{}", t);
-    let y = 5;
-    makes_copy(y);
-    println!("{}", y);
-
-    let s4 = String::from("hello");
-    let len = calculate_length(&s4);
-    println!("The length of '{}' is {}.", s4, len);
-
-    // let s5 = String::from("hello");
-    // change(&s5);
-
-    let mn = String::from("hello world");
-    let word = first_word(&mn);
-    // mn.clear();
-    println!("The first word is: {}", word);
-
-    // let width1 = 30;
-    // let height1 = 50;
-
-    let rect1 = Rectangle {
-        width: 30,
-        height: 50,
-    };
-    dbg!(&rect1);
-    // println!("rect1 is {:#?}", rect1);
-    // println!(
-    //     "The area of the rectangle is {} square pixels.",
-    //     area(&rect1)
-    // );
     println!(
-        "The area of the rectangle is {} square pixels.",
+        "Car order 1: {:?}, Hard top = {}, {:?}, {}, {} miles",
-        rect1.area()
+        car.age.0, car.color, car.convertible, car.color, car.age.1
     );
 
-    let rect2 = Rectangle::square(3);
+    car = car_factory(String::from(colors[1]), Transmission::SemiAuto, false, 1);
     println!(
-        "The area of the rectangle is {} square pixels.",
+        "Car order 1: {:?}, Hard top = {}, {:?},{:?}, {}, {} miles",
-        rect2.area()
+        car.age.0, car.color, car.convertible, car.transmission, car.color, car.age.1
+    );
+
+    car = car_factory(String::from(colors[2]), Transmission::Manual, false, 101);
+    println!(
+        "Car order 1: {:?}, Hard top = {}, {:?}, {}, {} miles",
+        car.age.0, car.color, car.convertible, car.color, car.age.1
     );
 }
-
-fn another_function(a: i32, char: char) -> i32 {
-    println!("Another function.");
-    println!("The value of a is: {}", a);
-    println!("The value of char is: {}", char);
-    5
-}
-
-fn fibonacci_function(n: i32) -> i32 {
-    if n == 0 {
-        return 0;
-    } else if n == 1 {
-        return 1;
-    } else {
-        return fibonacci_function(n - 1) + fibonacci_function(n - 2);
-    }
-}
-
-fn celsius_to_fahrenheit(celsius: f64) -> f64 {
-    celsius * 1.8 + 32.0
-}
-
-fn fahrenheit_to_celsius(fahrenheit: f64) -> f64 {
-    (fahrenheit - 32.0) / 1.8
-}
-
-fn takes_ownership(some_string: String) {
-    // some_string 进入作用域
-    println!("{some_string}");
-} // 这里，some_string 移出作用域并调用 `drop` 方法。
-  // 占用的内存被释放
-
-fn makes_copy(some_integer: i32) {
-    // some_integer 进入作用域
-    println!("{some_integer}");
-} // 这里，some_integer 移出作用域。没有特殊之处
-
-fn calculate_length(s: &String) -> usize {
-    s.len()
-}
-
-// fn change(some_string: &String) {
-//     some_string.push_str(", world");
-// }
-
-fn first_word(s: &String) -> &str {
-    let bytes = s.as_bytes();
-
-    for (i, &item) in bytes.iter().enumerate() {
-        if item == b' ' {
-            return &s[..i];
-        }
-    }
-
-    &s[..]
-}
-
-// fn area(width: u32, height: u32) -> u32 {
-//     width * height
-// }
-
-#[derive(Debug)]
-struct Rectangle {
-    width: u32,
-    height: u32,
-}
-
-impl Rectangle {
-    fn area(&self) -> u32 {
-        self.width * self.height
-    }
-}
-
-impl Rectangle {
-    fn square(size: u32) -> Rectangle {
-        Rectangle {
-            width: size,
-            height: size,
-        }
-    }
-}