Please help with a newbie question

Hello everyone,
I just started reading the <jumping into c++>, it's a fantastic book.
I got a question about sample Code 9: string_append.cpp
I made 2 changes with the sample, then the program stopped working properly.
I better show you:

Code:

#include <iostream>
#include <string>
using namespace std;
int main ()
{
string user_first_name;
string user_last_name;
string user_full_name = user_first_name + " " + user_last_name;
cout << "Please enter your first name: ";
cin >> user_first_name;
cout << "Please enter your last name: ";
//cin >> user_last_name;
getline(cin, user_last_name, '\n');
//string user_full_name = user_first_name + " " + user_last_name;
cout << "Your name is: " << user_full_name << "\n";
cin.get();
cin.ignore();
}

As you can see, the two "//" commented out lines were originally in the sample, but I put string user full name on top, and used getline instead of cin. Then this happened:

If I only change the position of string user full name, without changing cin to getline, this is what happened: no display

I'm using visual studio 2010, and I have no idea why this is happening, please help
thanks a lot guys

This is being caused by mixing the extraction operator>> with getline(). The extraction operator leaves the end of line character in the stream that getline() accepts for it's complete input. You may want to check this boards FAQ, there is an entry on how to solve this problem.

Jim

>>string user_full_name = user_first_name + " " + user_last_name;
>>cout << "Please enter your first name: ";
>>cin >> user_first_name;
Also, clearly, there is no point in putting together the full name before you've actually collected the first and last names.
Remember: code is executed sequentially, so only before your cout statement that prints the full name do you have the first and last names stored in your variables.