closures.rs

fn main() {
    let outer_var = String::from("23");

    fn function(input: i32) -> i32 {
        input
        // + outer_var
    }

    fn call_closure<F>(f: F, arg: i32)
    where
        F: FnOnce(i32) -> i32,
    {
        f(arg);
    }

    let test = |x: i32| {
        std::mem::drop(outer_var);
        return x + 1;
    };

    call_closure(test, 1);

    fn a_function_that_returns_closure() -> impl FnOnce() {
        let mut x = "hy".to_owned();

        let clo = move || {
            x += "fy";
            println!("x is {x}");
            std::mem::drop(x);
        };

        clo
    }

    let xx = a_function_that_returns_closure();
    xx();

    let vec1 = vec![
        String::from("A"),
        String::from("B"),
        String::from("C"),
        String::from("D"),
    ];

    let is_present = vec1.iter().any(|ele| *ele == String::from("C"));
    println!("is_present : {is_present}");

    let is_find = vec1.iter().find(|ele| **ele == String::from("C"));
    println!("is_find : {:?}", is_find);

    let position_of_b = vec1.iter().position(|ele| *ele == String::from("B"));
    println!("position_of_b : {:?}", position_of_b);
}