public void DropSetXTest()
{
CStack cs = new CStack();
cs.entry = "1";
cs.Enter();
cs.entry = "2";
cs.Enter();
cs.entry = "3";
cs.Enter();
Assert.AreEqual(cs.T, 0);
Assert.AreEqual(cs.Z, 1);
Assert.AreEqual(cs.Y, 2);
Assert.AreEqual(cs.X, 3);
cs.DropSetX(4);
Assert.AreEqual(cs.T, 0);
Assert.AreEqual(cs.Z, 0);
Assert.AreEqual(cs.Y, 1);
Assert.AreEqual(cs.X, 4);
}