Write a program which reads in a dynamic # of floats from the user.

You should have a function for input, a function to compute the
average, a function to compute the minimum and a function to compute
the maximum.  You should use vectors and pass the vector to 
functions. 

Never pass "vector<int>" objects to your functions.
Always pass either:  
       "vector<int> &" or
       "const vector<int> &",
whichever is most appropriate for your function.