X-Git-Url: https://git.ralfj.de/rust-101.git/blobdiff_plain/9ae2b045dd1772c02f7013953dd4108a99bd2c74..8d09a95e8d64b2fd3a30940fcedbc41ae2c59396:/workspace/src/part08.rs?ds=inline diff --git a/workspace/src/part08.rs b/workspace/src/part08.rs index d03934a..5ddcb33 100644 --- a/workspace/src/part08.rs +++ b/workspace/src/part08.rs @@ -7,7 +7,7 @@ use part05::BigInt; // So, let us write a function to "add with carry", and give it the appropriate type. Notice Rust's native support for pairs. fn overflowing_add(a: u64, b: u64, carry: bool) -> (u64, bool) { - let sum = u64::wrapping_add(a, b); + let sum = a.wrapping_add(b); // If an overflow happened, then the sum will be smaller than *both* summands. Without an overflow, of course, it will be // at least as large as both of them. So, let's just pick one and check. if sum >= a { @@ -15,7 +15,7 @@ fn overflowing_add(a: u64, b: u64, carry: bool) -> (u64, bool) { // **Exercise 08.1**: Write the code to handle adding the carry in this case. unimplemented!() } else { - // The addition *did* overflow. It is impossible for the addition of the carry + // Otherwise, the addition *did* overflow. It is impossible for the addition of the carry // to overflow again, as we are just adding 0 or 1. unimplemented!() } @@ -56,11 +56,11 @@ impl ops::Add for BigInt { } } -// ## Traits and borrowed types +// ## Traits and reference types // Writing this out becomes a bit tedious, because trait implementations (unlike functions) require full explicit annotation // of lifetimes. Make sure you understand exactly what the following definition says. Notice that we can implement a trait for -// a borrowed type! +// a reference type! impl<'a, 'b> ops::Add<&'a BigInt> for &'b BigInt { type Output = BigInt; fn add(self, rhs: &'a BigInt) -> Self::Output { @@ -76,7 +76,9 @@ impl<'a, 'b> ops::Add<&'a BigInt> for &'b BigInt { // Rust calls a bunch of definitions that are grouped together a *module*. You can put the tests in a submodule as follows. #[cfg(test)] mod tests { - #[test] + use part05::BigInt; + + /*#[test]*/ fn test_add() { let b1 = BigInt::new(1 << 32); let b2 = BigInt::from_vec(vec![0, 1]);