Whats's the difference between a prime minister and a president in a country where that has both?

Question

Like in some European countries?

Answer 1

That's how it is in Europe:
Usually, the prime minister is the one who runs the country, he is the boss of all ministers, and all the ministers together are the executive.
The President is nominally head of the state, but he is just a representative figure. He doesn't rule as such. He is often taking part in diplomacy, etc. In most countries he is the one who will command the country's forces in a war.
The situation is similar in most European monarchies, with the prime minister ruling and the King or Queen being a public figure only.
In other parts of the world this may not apply, especially in non-democratic countries with strong power struggles.

Answer 2

Rumtscho's stuff is very good. It also depends on the nation's constitution, its legislature, and laws.

In Australia, the people usually vote for representatives belonging to a party, but the party actually determines who leads. If the party is dissatisfied with the leader, the party in power can also replace him without the consent of the people.

Answer 3

prime minister is like CEO of the country who controls and lead all the departments [ministries] and is responsible for all the decisions taken by them, President is nothing but the stamp of PM, he just have to sign all the decisions taken by ministries...