Write the implementation (.cpp file) of the Counter class from the previous exercise. Here is the full specification of the class : The class contains: * A data member counter of type int . * A constructor that accepts no arguments and initializes the counter data member to 0. * A function called increment that accepts no parameters and returns no value. increment adds one to the counter data member. * A function called getValue that accepts no parameters. It returns the value of the instance variable counter.