My answer to Exercise from 8th part of RustBook Rust lang

exercise8-3-1.rs

use std::collections::HashMap;

fn main() {
    let integer_list = [
        20, 47, 85, 99, 80, 86, 90, 89, 74, 9, 51, 78, 86, 36, 4, 68, 71, 42, 1, 64,
    ];
    let mut result_vec: Vec<f64> = vec![0.0; 3];

    result_vec[0] = integer_list.iter().sum::<i64>() as f64 / integer_list.iter().count() as f64;
    {
        let mut list_copy = integer_list.clone();
        list_copy.sort();
        result_vec[1] = list_copy[list_copy.iter().count() / 2] as f64;
    }
    {
        let mut count_map = HashMap::new();
        for i in &integer_list {
            let count = count_map.entry(i).or_insert(0);
            *count += 1;
        }
        let mut max = [0, 0];
        for (key, value) in &count_map {
            if *value > max[0] {
                max[0] = *value;
                max[1] = **key;
            }
        }
        result_vec[2] = max[1] as f64;
    }

    println!("{:?}", result_vec);
}

exercise8-3-3.rs

use std::collections::HashMap;
use std::io::stdin;

fn main() {
    println!("Hello! This is Employees terminal program");
    println!("Enter names of employees and departments in format \"Add {{Employee-name}} to {{department-name}}\"");
    println!("To get list of all people - people-list; to list by departments - dep-list department-name");
    println!("To exit - type \"exit\" or hit Ctrl + C\nGood luck!");

    let mut user_input = String::new();
    let mut employees: HashMap<String, Vec<String>> = HashMap::new();
    loop {
        user_input.clear();

        match stdin().read_line(&mut user_input) {
            Ok(_) => (),
            Err(error) => {
                println!("Failed to input: {}", error);
                continue;
            }
        }
        let user_input_array: Vec<&str> = user_input.trim().split(" ").collect();
        if user_input_array.len() == 1 {
            match user_input_array[0].to_lowercase().as_ref() {
                "exit" => {
                    println!("Bye! Exitting...");
                    break;
                }
                "people-list" => {
                    let mut people: Vec<String> = Vec::new();
                    for names in employees.values() {
                        for name in names {
                            people.push(name.to_string());
                        }
                    }
                    people.sort();
                    println!("All persons in company: ");
                    for person in &people {
                        println!("{} ", person);
                    }
                    continue;
                }
                _ => {
                    println!("There is no such command: {}", user_input_array[0]);
                    continue;
                }
            }
        }

        if user_input_array.len() == 2 {
            if user_input_array[0].to_lowercase() == "dep-list" {
                if let Some(list) = employees.get(user_input_array[1]) {
                    for person in list {
                        println!("{}", person);
                    }
                } else {
                    println!("There is no department named {}", user_input_array[1]);
                }
                continue;
            } else {
                println!("There is no such command: {}", user_input_array[0]);
                continue;
            }
        }

        if user_input_array.len() == 4 {
            if user_input_array[0].to_lowercase() == "add"
                && user_input_array[2].to_lowercase() == "to"
            {
                let name = user_input_array[1].to_string();
                let department = user_input_array[3].to_string();
                employees.entry(department).or_insert(Vec::new()).push(name);
            } else {
                println!("Unknown command: {}", user_input_array.join(" "));
            }
        }
    }
}