Lesson 4 of 11
Functions
Pass an argument into a function and trace the value it returns.
main.rs
fn main() { let answer = double(4); println!("{answer}");}fn double(n: i32) -> i32 { n * 2}Program state
- Program
- Ready
Step 1 of 6
The program is ready to call a function.
What’s happening
A function lets you name and reuse a piece of code. The parameter n: i32 tells callers what kind of value to pass. The arrow and type, -> i32, tell callers what they get back.
In double, n * 2 is the final expression. With no semicolon after it, its value becomes the function’s return value.
Read more in The Rust Book