C - Static Keyword

Usage	Effect
inside a function	remains even after the function call is long gone
modify a global variable	private to a certain file
modify a function	making those functions visible only to the file itself

C++ - const Keyword

Use the keyword const to signify (to developers, not just the compiler) that a variable does not change).

/**
 * This method doesn't change its object
 * @param[in] obj Reference to a constant MyObj
 * @return A constant reference to obj
 */
const MyObj& MyObj::myMethod(const MyObj &obj) const
{
    return obj;
}