complete part 10

[rust-101.git] / src / part08.rs

diff --git a/src/part08.rs b/src/part08.rs
index feb2abc5a36f7bbee3f81f831ff9499476d27611..d6b6782e5fb5d2f42e11d073a3182894acd9b96c 100644 (file)
--- a/src/part08.rs
+++ b/src/part08.rs
@@ -26,11 +26,13 @@ fn overflowing_add(a: u64, b: u64, carry: bool) -> (u64, bool) {
     if sum >= a {
         // The addition did not overflow. <br/>
         // **Exercise 08.1**: Write the code to handle adding the carry in this case.
-        unimplemented!()
+        let sum_total = u64::wrapping_add(sum, if carry { 1 } else { 0 });      /*@@*/
+        let had_overflow = sum_total < sum;                                     /*@@*/
+        (sum_total, had_overflow)                                               /*@@*/
     } 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.
-        (sum + if carry { 1 } else { 0 }, true)                     /*@*/
+        (sum + if carry { 1 } else { 0 }, true)                                 /*@*/
     }
 }
 
@@ -82,7 +84,10 @@ impl ops::Add<BigInt> for BigInt {
             carry = new_carry;                                                  /*@*/
         }
         // **Exercise 08.2**: Handle the final `carry`, and return the sum.
-        unimplemented!()
+        if carry {                                                              /*@@*/
+            result_vec.push(1);                                                 /*@@*/
+        }                                                                       /*@@*/
+        BigInt { data: result_vec }                                             /*@@*/
     }
 }
 
@@ -113,7 +118,9 @@ impl<'a, 'b> ops::Add<&'a BigInt> for &'b BigInt {
 //@ Rust would not bother compiling them when you just build your program for normal use. Other than that, tests work as usually.
 #[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]);