# Introduction In this lab, we learn how to write functions in Rust. Functions are declared using the `fn` keyword, and their arguments are type annotated. The return type, if applicable, is specified after an arrow `->`. The final expression in the function serves as the return value, but the `return` statement can be used to return a value earlier. The lab provides an example of rewriting the FizzBuzz program using functions, demonstrating the use of functions that return boolean values, functions that return the unit type `()`, and functions without specified return types. > **Note:** If the lab does not specify a file name, you can use any file name you want. For example, you can use `main.rs`, compile and run it with `rustc main.rs && ./main`.
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