Old snapshot `BigIntegerLibrary-2005.03.30'; see the ChangeLog file.

[bigint/bigint.git] / BigInteger.cc

diff --git a/BigInteger.cc b/BigInteger.cc
index 69d2dd7..5acf459 100644 (file)
--- a/BigInteger.cc
+++ b/BigInteger.cc
@@ -358,9 +358,11 @@ void BigInteger::subtract(const BigInteger &a, const BigInteger &b) {
        // If a is zero, copy b and flip its sign.  If b is zero, copy a.
        if (a.sign == zero) {
                BigUnsigned::operator =(b);
-               sign = Sign(-sign);
+               // Take the negative of _b_'s, sign, not ours.
+               // Bug pointed out by Sam Larkin on 2005.03.30.
+               sign = Sign(-b.sign);
        } else if (b.sign == zero)
-    operator =(a);
+               operator =(a);
        // If their signs differ, take a.sign and add the magnitudes.
        else if (a.sign != b.sign) {
                sign = a.sign;