Function apply_twice

tests/binary/fn_pointers/src/main.rs:69–71

(f: fn(f64) -> f64, x: f64)

}

fn apply_twice(f: fn(f64) -> f64, x: f64) -> f64 {
    f(f(x))
}

fn choose_curve(which: i32) -> fn(f64) -> f64 {
    if which == 0 {