If you go to Wikipedia and type "List of heads of state", you'll find a list of current heads of state (and heads of government, when they are not the same person). I'll leave it to you to check which of these qualify as "presidents".

It depends on what the precedence has to do with. If it is inheriting an estate with no will it will depend on the state in question. In most places the grandfather will have precedence.

The power to enter into treaties with other countries and make executive agreements with other heads of state is known as the power of foreign diplomacy or treaty-making authority.

benigno simeon "noynoy" conjuanco aquino III

1990 - 2005 > Sam Nujoma

2006 - present > Hifikepunye Pohamba