Update ex5_14.cpp
Update ex5_14.cpp

add the solution with 'while' loop.
akanezorap/CppPrimer,pezy/CppPrimer,laohei889/CppPrimer,akanezorap/CppPrimer,Sublele/CppPrimer,Sublele/CppPrimer,pezy/CppPrimer,laohei889/CppPrimer