1. Create a Rust project to work on during this chapter with cargo new chapter_four.
2. Navigate into the newly-created chapter_four folder. For the rest of this chapter, we will assume that your command line is currently in this directory.
3. Inside the src folder, create a new folder called bin.
4. Delete the generated lib.rs file, as we are not creating a library.

5. Open the Cargo.toml file that was generated earlier for you.

6. Under [dependencies], add the following line:

 csv = "1.0.0-beta.5"

7. If you want, you can go to csv's crates.io page (https://crates.io/crates/csv) to check for the newest version and use that one instead.
8. In the src/bin folder, create a file called csv.rs
9. Add the following code and run it with cargo run --bin csv:

1    extern crate csv;
2 
3    use std::io::{BufReader, BufWriter, Read, Seek, SeekFrom,
  Write};
4    use std::fs::OpenOptions;
5 
6    fn main() {
7      let file = OpenOptions::new()
8        .read(true)
9        .write(true)
10       .create(true)
11       .open("solar_system_compared_to_earth.csv")
12       .expect("failed to create csv file");
13 
14     let buf_writer = BufWriter::new(&file);
15     write_records(buf_writer).expect("Failed to write csv");
16 
17     let mut buf_reader = BufReader::new(&file);
18     buf_reader
19       .seek(SeekFrom::Start(0))
20       .expect("Failed to jump to the beginning of the csv");
21     read_records(buf_reader).expect("Failed to read csv");
22   }
23 
24   fn write_records<W>(writer: W) -> csv::Result<()>
25   where
26   W: Write,
27   {
28     let mut wtr = csv::Writer::from_writer(writer);
29 
30     // The header is just a normal record
31     wtr.write_record(&["name", "radius", "distance_from_sun", 
32     "gravity"])?;
33 
34     wtr.write_record(&["Mercury", "0.38", "0.47", "0.38"])?;
35     wtr.write_record(&["Venus", "0.95", "0.73", "0.9"])?;
36     wtr.write_record(&["Earth", "1", "1", "1"])?;
37     wtr.write_record(&["Mars", "0.53", "1.67", "0.38"])?;
38     wtr.write_record(&["Jupiter", "11.21", "5.46", "2.53"])?;
39     wtr.write_record(&["Saturn", "9.45", "10.12", "1.07"])?;
40     wtr.write_record(&["Uranus", "4.01", "20.11", "0.89"])?;
41     wtr.write_record(&["Neptune", "3.88", "30.33", "1.14"])?;
42     wtr.flush()?;
43     Ok(())
44   }
45 
46   fn read_records<R>(reader: R) -> csv::Result<()>
47   where
48   R: Read,
49   {
50     let mut rdr = csv::Reader::from_reader(reader);
51     println!("Comparing planets in the solar system with the 
52     earth");
53     println!("where a value of '1' means 'equal to earth'");
54     for result in rdr.records() {
55       println!("-------");
56       let record = result?;
57       if let Some(name) = record.get(0) {
58         println!("Name: {}", name);
59       }
60       if let Some(radius) = record.get(1) {
61         println!("Radius: {}", radius);
62       }
63       if let Some(distance) = record.get(2) {
64         println!("Distance from sun: {}", distance);
65       }
66       if let Some(gravity) = record.get(3) {
67         println!("Surface gravity: {}", gravity);
68       }
69     }
70     Ok(())
71   }