Higher-Order Functions

Functions that take or return other functions.

Difficulty

Intermediate

Code

fn apply<F: Fn(i32) -> i32>(f: F, x: i32) -> i32 {
    f(x)
}

fn make_adder(n: i32) -> impl Fn(i32) -> i32 {
    move |x| x + n
}

fn main() {
    let double = |x| x * 2;
    println!("apply(double, 5) = {}", apply(double, 5));

    let add_10 = make_adder(10);
    println!("add_10(3) = {}", add_10(3));
}

Explanation

This example demonstrates how to use higher-order functions in Rust. Read the code carefully to understand the flow. Pay attention to where values are created, borrowed, moved, or consumed.

Key Concepts

• Rust's strong type system catches errors at compile time
• Ownership and borrowing rules ensure memory safety
• Pattern matching makes code expressive and exhaustive

Related Topics

Browse more examples in the functions category to build a complete understanding of this topic.