Merge pull request #793 from AnthonyMichaelTDM/main

Rust implementation of 91_Train

91_Train/rust/Cargo.toml

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+[package]
+name = "rust"
+version = "0.1.0"
+authors = ["AnthonyMichaelTDM <68485672+AnthonyMichaelTDM@users.noreply.github.com>"]
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+rand = "0.8.5"

91_Train/rust/README.md

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+Original source downloaded [from Vintage Basic](http://www.vintage-basic.net/games.html)
+
+Conversion to [Rust](https://www.rust-lang.org/) by Anthony Rubick [AnthonyMichaelTDM](https://github.com/AnthonyMichaelTDM)

91_Train/rust/src/lib.rs

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+/*
+ lib.rs contains all the logic of the program
+*/
+use rand::{Rng, prelude::thread_rng}; //rng
+use std::error::Error; //better errors
+use std::io::{self, Write}; //io interactions
+use std::{str::FromStr, fmt::Display}; //traits
+
+//DATA
+
+/// handles setup for the game
+pub struct Config {
+}
+impl Config {
+    /// creates and returns a new Config from user input
+    pub fn new() -> Result<Config, Box<dyn Error>> {
+        //DATA
+        let config: Config = Config { 
+        };
+
+        //return new config
+        return Ok(config);
+    }
+}
+
+/// run the program
+pub fn run(_config: &Config) -> Result<(), Box<dyn Error>> {
+    //DATA
+    let mut rng = thread_rng();
+
+    let mut speed_train_1;
+    let mut time_difference;
+    let mut speed_train_2;
+
+    let mut guess;
+    let mut answer;
+
+    let mut error:f32; 
+
+    //Game loop
+    loop {
+        //initialize variables
+        speed_train_1 =  rng.gen_range(40..65);
+        time_difference = rng.gen_range(5..20); 
+        speed_train_2 = rng.gen_range(20..39);
+
+        //print starting message / conditions
+        println!("A CAR TRAVELING {} MPH CAN MAKE A CERTAIN TRIP IN\n{} HOURS LESS THAN A TRAIN TRAVELING AT {} MPH",speed_train_1,time_difference,speed_train_2);
+        println!();
+
+        //get guess
+        guess = loop {
+            match get_number_from_input("HOW LONG DOES THE TRIP TAKE BY CAR?",0,-1) {
+                Ok(num) => break num,
+                Err(err) => {
+                    eprintln!("{}",err);
+                    continue;
+                },
+            }
+        };
+
+        //calculate answer and error
+        answer = time_difference * speed_train_2 / (speed_train_1 - speed_train_2);
+        error = ((answer - guess) as isize).abs() as f32 * 100.0/(guess as f32) + 0.5;
+
+        //check guess against answer
+        if error > 5.0 {
+            println!("SORRY, YOU WERE OFF BY {} PERCENT.", error);
+            println!("CORRECT ANSWER IS {} HOURS.",answer);
+        } else {
+            println!("GOOD! ANSWER WITHIN {} PERCENT.", error);
+        }
+
+        //ask user if they want to go again
+        match get_string_from_user_input("ANOTHER PROBLEM (Y/N)") {
+            Ok(s) => if !s.to_uppercase().eq("Y") {break;} else {continue;},
+            _ => break,
+        }
+    }
+
+    //return to main
+    Ok(())
+}
+
+/// gets a string from user input
+fn get_string_from_user_input(prompt: &str) -> Result<String, Box<dyn Error>> {
+    //DATA
+    let mut raw_input = String::new();
+
+    //print prompt
+    print!("{}", prompt);
+    //make sure it's printed before getting input
+    io::stdout().flush().expect("couldn't flush stdout");
+
+    //read user input from standard input, and store it to raw_input, then return it or an error as needed
+    raw_input.clear(); //clear input
+    match io::stdin().read_line(&mut raw_input) {
+        Ok(_num_bytes_read) => return Ok(String::from(raw_input.trim())),
+        Err(err) => return Err(format!("ERROR: CANNOT READ INPUT!: {}", err).into()),
+    }
+}
+/// generic function to get a number from the passed string (user input)
+/// pass a min lower  than the max to have minimum and maximum bounds
+/// pass a min higher than the max to only have a minimum bound
+/// pass a min equal   to  the max to only have a maximum bound
+/// 
+/// Errors:
+/// no number on user input
+fn get_number_from_input<T:Display + PartialOrd + FromStr>(prompt: &str, min:T, max:T) -> Result<T, Box<dyn Error>> {
+    //DATA
+    let raw_input: String;
+    let processed_input: String;
+
+
+    //input loop
+    raw_input = loop {
+        match get_string_from_user_input(prompt) {
+            Ok(input) => break input,
+            Err(e) => {
+                eprintln!("{}",e);
+                continue;
+            },
+        }
+    };
+
+    //filter out non-numeric characters from user input
+    processed_input = raw_input.chars().filter(|c| c.is_numeric()).collect();
+
+    //from input, try to read a number
+    match processed_input.trim().parse() {
+        Ok(i) => {
+            //what bounds must the input fall into
+            if min < max {  //have a min and max bound: [min,max]
+                if i >= min && i <= max {//is input valid, within bounds
+                    return Ok(i); //exit the loop with the value i, returning it
+                } else { //print error message specific to this case
+                    return Err(format!("ONLY BETWEEN {} AND {}, PLEASE!", min, max).into());
+                } 
+            } else if min > max { //only a min bound: [min, infinity)
+                if i >= min {
+                    return Ok(i);
+                } else {
+                    return Err(format!("NO LESS THAN {}, PLEASE!", min).into());
+                }
+            } else { //only a max bound: (-infinity, max]
+                if i <= max {
+                    return Ok(i);
+                } else {
+                    return Err(format!("NO MORE THAN {}, PLEASE!", max).into());
+                }
+            }
+        },
+        Err(_e) => return Err(format!("Error: couldn't find a valid number in {}",raw_input).into()),
+    }
+}

91_Train/rust/src/main.rs

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+use std::process;//allows for some better error handling
+
+mod lib; //allows access to lib.rs
+use lib::Config;
+
+/// main function
+/// responsibilities:
+/// - Calling the command line logic with the argument values
+/// - Setting up any other configuration
+/// - Calling a run function in lib.rs
+/// - Handling the error if run returns an error
+fn main() {
+    //greet user
+    welcome();
+
+    // set up other configuration
+    let mut config = Config::new().unwrap_or_else(|err| {
+        eprintln!("Problem configuring program: {}", err);
+        process::exit(1);
+    });
+
+    // run the program
+    if let Err(e) = lib::run(&mut config) {
+        eprintln!("Application Error: {}", e); //use the eprintln! macro to output to standard error
+        process::exit(1); //exit the program with an error code
+    }
+
+    //end of program
+    println!("THANKS FOR PLAYING!");
+}
+
+/// print the welcome message
+fn welcome() {
+    println!("
+                                Train
+              CREATIVE COMPUTING  MORRISTOWN, NEW JERSEY
+
+
+TIME - SPEED DISTANCE EXERCISE
+    ");
+}