Update ex5_14.cpp

In the previous version, when you successively input same strings, then end the loop by ctrl+z(windows), the result is no duplicated words, which is not accord with our input.(eg. input three "123" and then ended with ctrl+z). 
The reason is that if the inputs are same from start, we will never enter the else branch where assign value to variable 'max_duplicated'.
So the operation on 'max_duplicated' should be done only when the 'count > max_duplicated.second + 1', which shows that continously duplicated inputs are tested. And when the input is not same with the previous, we should set the count for the new string to 1.
Update ex5_14.cpp

Adjust the format for code comparison.
Update ex5_14.cpp

Modify a bug for testing the count and max_duplicated.second, to make sure it will update max_duplicated.second only when a word is successively repeated more than two times.
Merge pull request #28 from AlexHuang1734/master

Solve a bug that the original code failed to handle consecutively identical input.