Differencies using const [duplicate]

This question already has an answer here:

• C++ Const Usage Explanation 12 answers

What is the difference in fucntion definition between

• 1. foo(Object &object) const
• 2. foo(const Object &object)

and

• 3. foo(const Object &object) const

I know that in first variant object cannot be changed in function. But what about the 2. and 3.? isn`t the 1. and 3. the same? Thank you.