fn main() {

fn divide(a: i64, b: i64) -> (i64, bool) {
    if b == 0 { return (0, false); }
    (a / b, true)
}
let (q, ok) = divide(7, 2);

assert_eq!((q,ok),(3,true)); assert_eq!(divide(7,0),(0,false)); assert_eq!(divide(-7,3),(-2,true));
}