# `?` operator ## Example Execute the following command to run [`./solutions/examples/question.rs`](https://github.com/Cyfrin/rust-crash-course/blob/main/topics/question/solutions/examples/question.rs) ```shell cargo run --example question ``` ## Exercises Exercises are in [`./exercises/src/lib.rs`](https://github.com/Cyfrin/rust-crash-course/blob/main/topics/question/exercises/src/lib.rs) ### Exercise 1 ```rust pub fn sum(nums: &[&str]) -> Result<u32, String> { todo!(); } ``` Parse the slice of string slices into `u32` and return their sum. Call the `parse` function to parse a `&str` into `u32`. Use `?` to make your code shorter. ### Test ```shell cargo test ```