# Conventions

In the previous chapter, we saw the following directory hierarchy:

    foo
    ├── Cargo.toml
    └── src
        └── main.rs

Suppose that we wanted to have two binaries in the same project, though. What then?

It turns out that `cargo` supports this. The default binary name is `main.rs`, as we saw before, but you can add additional binaries by placing them in a `bin/` directory:

    foo
    ├── Cargo.toml
    └── src
        ├── main.rs
        └── bin
            └── my_other_bin.rs

To tell `cargo` to compile or run this binary as opposed to the default or other binaries, we just pass `cargo` the `--bin my_other_bin` flag, where `my_other_bin` is the name of the binary we want to work with.

In addition to extra binaries, `cargo` supports more features such as benchmarks, tests, and examples.

In the next chapter, we will look more closely at tests.