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BuddyHawks 10-17-2004 08:24 PM

C++ Basic string help
 
I'm programming in C++ and want to read a list of names from an input file and store it as a string vector. Would this code work?
Is there a better way that’s not too advanced?
-----------------------------------------------------------------------

ifstream fin;
fin.open("names.txt");

vector<string> NAME;
string person;

while( !fin.fail( ) ){
fin >> person;
NAME.push_back(person)
}

fin.close;

-------------------------------------------------------------------
Thanks for any advice!

formerScientist 10-18-2004 09:16 AM

Careful, do the names contain white space? When using the extraction operator (>>) it will read everything until the next chunk of whitespace. So if your file looks like:

John Doe
Mary Smith

Your vector will contain 4 elements:
vec[0] == "John"
vec[1] == "Doe"
vec[2] == "Mary"
vec[3] == "Smith"

if you want the newline to represent your delimeter you'll have to use the std::getline function to read a line of text at a time. Example:

std::ifstream fin("input.txt");

std::string person;
std::vector<std::string> names;
while (std::getline(fin, person))
{
names.push_back(person);
}

bingle 10-18-2004 10:16 AM

Quote:

Originally Posted by formerScientist
if you want the newline to represent your delimeter you'll have to use the std::getline function to read a line of text at a time.

Or if you need to stick with the regular stream operator (and your names will always be in the form First Last) you can just read in two at a time, concatenate them, and store the result string in your vector.

Bingle

formerScientist 10-19-2004 11:22 AM

The getline routine is faster than two extractions and a concatination plus the resulting code is cleaner, easier to understand, easier to modify and more robust. More robust because the text file could now easily contain Mr. John P. Doe Jr. on a line and that would be read-in correctly without modifying the code.

bingle 10-20-2004 05:00 PM

Quote:

Originally Posted by formerScientist
The getline routine is faster than two extractions and a concatination plus the resulting code is cleaner, easier to understand, easier to modify and more robust. More robust because the text file could now easily contain Mr. John P. Doe Jr. on a line and that would be read-in correctly without modifying the code.

That's true, which is why I gave the disclaimer "if you want to stick with the standard stream operator". It seems like a lot of people who ask questions here are doing so for courses and things, and giving them answers they haven't encountered and don't understand yet might do more harm than good. Of course, I have no way of knowing if that's the case for BuddyHawks, but I thought I'd offer an option :-)

Bingle


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