# Code organization

When a single code block is getting larger, it should be decomposed into smaller pieces and should be organized in a proper manner. Rust supports different levels of code organization.

1. **Functions**
2. **Modules**

   Can be mapped to a,

   * **Inline module**
   * **File** 
   * **Directory hierarchy**
3. **Crates**

   Can be mapped to a,

   * **lib.rs file on the same executable crate**
   * **Dependency crate specified on Cargo.toml**

     Can be specified from,

     * **path**
     * **git repository**
     * **crates.io**
4. **Workspaces**

   Helps to manage multiple crates as a single project.

Let’s discuss one by one.

> 💡 To make examples more simpler, we use a simple function which prints `“Hello, world!”`. But regarding writing testable codes, always try to return the `String` from the function and print it when calling it, instead printing the String inside the function.