Thermodynamics: Entropy and its measurement

Entropy is a property of the system used to find the direction of a process.  It is calculated as [dQ(rev)/T] for a change of state. If we have a reversible process the change in total entropy (system + surrounding) is zero and if the process is irreversible, the change in total entropy is positive. Entropy is a state function, then why does it care about the process whether it is reversible or irreversible?

Change in entropy of system will remain same whether the process is reversible or irreversible. It depends only on the states of the system. But the states of surrounding will depend on the path taken to carry out changes in the state of a system. Therefore the states of surrounding will be different for different paths taken to carry out changes in system. Hence the entropy of surrounding will change with the path. That's why the total entropy change will depend on the path taken. For a reversible process minimum amount of heat is required to get a specified amount of work. Therefore the entropy change will be minimum i.e. zero. and if the process is irreversible the amount of heat will increase resulting in positive entropy change. So it is said that Entropy of the universe never decreases.