public void TestClearBit()
{
Assert.AreEqual(zero, zero.ClearBit(0));
Assert.AreEqual(zero, one.ClearBit(0));
Assert.AreEqual(two, two.ClearBit(0));
Assert.AreEqual(zero, zero.ClearBit(1));
Assert.AreEqual(one, one.ClearBit(1));
Assert.AreEqual(zero, two.ClearBit(1));
// TODO Tests for clearing bits in negative numbers
// TODO Tests for clearing extended bits
for (int i = 0; i < 10; ++i)
{
IBigInteger n = new BigInteger(128, _random);
for (int j = 0; j < 10; ++j)
{
int pos = _random.Next(128);
IBigInteger m = n.ClearBit(pos);
bool test = m.ShiftRight(pos).Remainder(two).Equals(one);
Assert.IsFalse(test);
}
}
for (int i = 0; i < 100; ++i)
{
IBigInteger pow2 = one.ShiftLeft(i);
IBigInteger minusPow2 = pow2.Negate();
Assert.AreEqual(zero, pow2.ClearBit(i));
Assert.AreEqual(minusPow2.ShiftLeft(1), minusPow2.ClearBit(i));
IBigInteger bigI = BigInteger.ValueOf(i);
IBigInteger negI = bigI.Negate();
for (int j = 0; j < 10; ++j)
{
string data = "i=" + i + ", j=" + j;
Assert.AreEqual(bigI.AndNot(one.ShiftLeft(j)), bigI.ClearBit(j), data);
Assert.AreEqual(negI.AndNot(one.ShiftLeft(j)), negI.ClearBit(j), data);
}
}
}