X-Git-Url: https://git.ralfj.de/rust-101.git/blobdiff_plain/9f6c55ebcab2e1d3073e8bb6c8c910d0116efee4..d5cee5ca7d257faea7f68b8812bf4d1a88ab5229:/workspace/src/part08.rs

diff --git a/workspace/src/part08.rs b/workspace/src/part08.rs
index 2d3b5d8..5ddcb33 100644
--- a/workspace/src/part08.rs
+++ b/workspace/src/part08.rs
@@ -7,15 +7,13 @@ 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 {
         // The addition did not overflow. <br/>
         // **Exercise 08.1**: Write the code to handle adding the carry in this case.
-        let sum_total = u64::wrapping_add(sum, if carry { 1 } else { 0 });      /*@@*/
-        let had_overflow = sum_total < sum;                                     /*@@*/
-        (sum_total, had_overflow)                                               /*@@*/
+        unimplemented!()
     } else {
         // 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.
@@ -54,18 +52,15 @@ impl ops::Add<BigInt> for BigInt {
             unimplemented!()
         }
         // **Exercise 08.2**: Handle the final `carry`, and return the sum.
-        if carry {                                                              /*@@*/
-            result_vec.push(1);                                                 /*@@*/
-        }                                                                       /*@@*/
-        BigInt { data: result_vec }                                             /*@@*/
+        unimplemented!()
     }
 }
 
-// ## 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 {
@@ -81,7 +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]);