测验2: exercises/quiz2.rs

题目

rust

// quiz2.rs
//
// This is a quiz for the following sections:
// - Strings
// - Vecs
// - Move semantics
// - Modules
// - Enums
//
// Let's build a little machine in the form of a function. As input, we're going
// to give a list of strings and commands. These commands determine what action
// is going to be applied to the string. It can either be:
// - Uppercase the string
// - Trim the string
// - Append "bar" to the string a specified amount of times
// The exact form of this will be:
// - The input is going to be a Vector of a 2-length tuple,
//   the first element is the string, the second one is the command.
// - The output element is going to be a Vector of strings.
//
// No hints this time!

// I AM NOT DONE

pub enum Command {
    Uppercase,
    Trim,
    Append(usize),
}

mod my_module {
    use super::Command;

    // TODO: Complete the function signature!
    pub fn transformer(input: ???) -> ??? {
        // TODO: Complete the output declaration!
        let mut output: ??? = vec![];
        for (string, command) in input.iter() {
            // TODO: Complete the function body. You can do it!
        }
        output
    }
}

#[cfg(test)]
mod tests {
    // TODO: What do we need to import to have `transformer` in scope?
    use ???;
    use super::Command;

    #[test]
    fn it_works() {
        let output = transformer(vec![
            ("hello".into(), Command::Uppercase),
            (" all roads lead to rome! ".into(), Command::Trim),
            ("foo".into(), Command::Append(1)),
            ("bar".into(), Command::Append(5)),
        ]);
        assert_eq!(output[0], "HELLO");
        assert_eq!(output[1], "all roads lead to rome!");
        assert_eq!(output[2], "foobar");
        assert_eq!(output[3], "barbarbarbarbarbar");
    }
}

这个测验主要针对以下内容：

字符串String
Vec
Move语义
模块
Enums

让我们通过函数的形式来构建小机器。我们提供字符串和命令作为输入，这些命令确定对字符串做什么操作，它们可以是：

字符串转大写
去除字符串前后空格
将bar追加到字符串后面指定次数

具体的形式为：

输入将会是一个长度为2的Vec
第一个元素是字符串，第二个元素是命令
输出的元素是字符串Vec

题目解析

rust

pub enum Command {
    Uppercase,
    Trim,
    Append(usize),
}

mod my_module {
    use super::Command;

    // TODO: Complete the function signature!
    pub fn transformer(input: ???) -> ??? { 
    pub fn transformer(input: Vec<(String, Command)>) -> Vec<String> { 
        // TODO: Complete the output declaration!
        let mut output: ??? = vec![];  
        let mut output: Vec<String> = vec![]; 
        for (string, command) in input.iter() {
            // TODO: Complete the function body. You can do it!
            match command {  
                Command::Uppercase => output.push(string.to_uppercase()),  
                Command::Trim => output.push(string.trim().to_string()), 
                Command::Append(n) => output.push(string.to_string() + "bar".repeat(*n).as_ref()), 
            } 
        }
        output
    }
}

#[cfg(test)]
mod tests {
    // TODO: What do we need to import to have `transformer` in scope?
    use ???; 
    use super::my_module::transformer;  
    use super::Command;

    #[test]
    fn it_works() {
        let output = transformer(vec![
            ("hello".into(), Command::Uppercase),
            (" all roads lead to rome! ".into(), Command::Trim),
            ("foo".into(), Command::Append(1)),
            ("bar".into(), Command::Append(5)),
        ]);
        assert_eq!(output[0], "HELLO");
        assert_eq!(output[1], "all roads lead to rome!");
        assert_eq!(output[2], "foobar");
        assert_eq!(output[3], "barbarbarbarbarbar");
    }
}

测验2: exercises/quiz2.rs ​

题目 ​

题目解析 ​

测验2: exercises/quiz2.rs

题目

题目解析