Low-Power Embedded Game
Level 1
10 Points
tuples
destructuring
Instructions
You are working on a game targeting a low-power embedded system and need to write several convenience functions which will be used by other parts of the game.
1. Calculate the quotient and remainder of a division
A quotient is the output of a division.
fn divmod(dividend: i16, divisor: i16) -> (i16, i16)Example:
assert_eq!(divmod(10, 3), (3, 1));2. Choose even-positioned items from an iterator
This will be helpful to enable a screen-buffer optimization, your boss promises.
Iterators are items which expose the methods defined by the Iterator trait. That documentation is fairly extensive, because they offer many methods; here are the most relevant properties:
- An iterator is an arbitrary-length stream of items
- They have an
enumeratemethod which returns a tuple(i, val)for each value - They have a
filtermethod which uses a closure to determine whether to yield an element of the iterator - They have a
mapmethod which uses a closure to modify elements of the iterator
Because your function can run on any kind of iterator, it uses impl to signify that this is a trait instance instead of a simple item. Likewise, the <Item=T> syntax just means that it doesn't matter what kind of item the iterator produces; your function can produce the even elements of any iterator.
fn evens<T>(iter: impl Iterator<Item=T>) -> impl Iterator<Item=T>Examples:
let mut even_ints = evens(0_u8..);
assert_eq!(even_ints.next(), Some(0));
assert_eq!(even_ints.next(), Some(2));
assert_eq!(even_ints.next(), Some(4));
assert_eq!(even_ints.next(), Some(6));let mut evens_from_odds = evens(1_i16..);
assert_eq!(evens_from_odds.next(), Some(1));
assert_eq!(evens_from_odds.next(), Some(3));
assert_eq!(evens_from_odds.next(), Some(5));
assert_eq!(evens_from_odds.next(), Some(7));3. Calculate the manhattan distance of a position from the origin
For mapping convenience, you have a tuple struct Position:
struct Position(i16, i16);You need to implement a method manhattan on Position which returns the manhattan distance of that position from the origin (Position(0, 0)).
impl Position {
fn manhattan(&self) -> i16
}Example:
assert_eq!(Position(3, 4).manhattan(), 7);Low-Power Embedded Game
Level 1
10 Points
tuples
destructuring
Instructions
You are working on a game targeting a low-power embedded system and need to write several convenience functions which will be used by other parts of the game.
1. Calculate the quotient and remainder of a division
A quotient is the output of a division.
fn divmod(dividend: i16, divisor: i16) -> (i16, i16)Example:
assert_eq!(divmod(10, 3), (3, 1));2. Choose even-positioned items from an iterator
This will be helpful to enable a screen-buffer optimization, your boss promises.
Iterators are items which expose the methods defined by the Iterator trait. That documentation is fairly extensive, because they offer many methods; here are the most relevant properties:
- An iterator is an arbitrary-length stream of items
- They have an
enumeratemethod which returns a tuple(i, val)for each value - They have a
filtermethod which uses a closure to determine whether to yield an element of the iterator - They have a
mapmethod which uses a closure to modify elements of the iterator
Because your function can run on any kind of iterator, it uses impl to signify that this is a trait instance instead of a simple item. Likewise, the <Item=T> syntax just means that it doesn't matter what kind of item the iterator produces; your function can produce the even elements of any iterator.
fn evens<T>(iter: impl Iterator<Item=T>) -> impl Iterator<Item=T>Examples:
let mut even_ints = evens(0_u8..);
assert_eq!(even_ints.next(), Some(0));
assert_eq!(even_ints.next(), Some(2));
assert_eq!(even_ints.next(), Some(4));
assert_eq!(even_ints.next(), Some(6));let mut evens_from_odds = evens(1_i16..);
assert_eq!(evens_from_odds.next(), Some(1));
assert_eq!(evens_from_odds.next(), Some(3));
assert_eq!(evens_from_odds.next(), Some(5));
assert_eq!(evens_from_odds.next(), Some(7));3. Calculate the manhattan distance of a position from the origin
For mapping convenience, you have a tuple struct Position:
struct Position(i16, i16);You need to implement a method manhattan on Position which returns the manhattan distance of that position from the origin (Position(0, 0)).
impl Position {
fn manhattan(&self) -> i16
}Example:
assert_eq!(Position(3, 4).manhattan(), 7);