public int GetCount(AtomPart part)
{
if (contents == null || contents.Count == 0)
{
return(0);
}
return(contents.FindAll(p => p == part).Count);
}
public void Undo()
{
if (contents.Count == 0)
{
return;
}
AtomPart last = contents[contents.Count - 1];
if (last == AtomPart.Proton)
{
SubtractProton();
}
else if (last == AtomPart.Neutron)
{
SubtractNeutron();
}
else
{
SubtractElectron();
}
Validate();
}
