Graduation Program

[ResidentBiscuit]

http://www.cplusplus.com/articles/N6vU7k9E/
So I've been working through this program. Been getting it set up and ready to go all day. I have a file with a bunch of different names for the bunnies, I'm just not sure how to get a specific line, or more of a random line from my file. Let's say I have one name per line, with 40 names, is there a function I can use to get a specific line, defined by a random number? I guess I'll also need a way to get the number of lines before hand, so I dont generate a random number that would be eof

[shacktar]

I have a file with a bunch of different names for the bunnies, I'm just not sure how to get a specific line, or more of a random line from my file.

You could read the whole file, placing each name into a vector. So, after reading a file with 40 names, you should have a vector with 40 names in it (you could use std::strings). You can limit your random number to the possible indexes into your vector.

[ResidentBiscuit]

That would make more sense. So just read into the vector until I hit eof? Then pick a random name from the vector?

[shacktar]

Yep, that's how I would do it. If your file doesn't change and it's of reasonable size then I would say that's the best approach.

[ResidentBiscuit]

Yea the file doesnt change during run time. It probably will never change again actually.

[ResidentBiscuit]

Ok, well right now I have this being done in my class, I feel like thats bad though. It means everytime a new object is made, this file is gonna be opened up, read into a vector, and closed. But I'm not sure where else to put this.

[ResidentBiscuit]

Ok I'm actually lost as to how to do this.

while(nameFile.eof() == false)
	{
		nameFile.getline(names[index] , 1000);
		index++;
	}

This doesnt work

[Albatross]

There's a separate getline function for std::strings. Sadly, those libraries aren't as tightly-integrated as they could be.
http://www.cplusplus.com/reference/string/getline/

Also, might I suggest using the push_back() function for adding those strings to your vector?
http://www.cplusplus.com/reference/stl/vector/push_back/

-Albatross

[ResidentBiscuit]

Ooh push_back() would be much better.
Now how I read one line into one element, the next line into next element, and so on. Not sure how to go about changing lines with this

[shacktar]

As Albatross showed, you can use std::getline to get one line from the file and you can use push_back to place that line into the vector.

e.g.

using namespace std;

string nameFromFile;
vector<string> namesVector;

while(!nameFile.eof())
{
    getline( nameFile, nameFromFile );
    namesVector.push_back( nameFromFile );
}

[ResidentBiscuit]

And that one would move down a line each iteration?

[shacktar]

Yes, getline moves the file pointer down to the next line.

[ResidentBiscuit]

:O Alright cool! Thanks you two. This is probably the most fstream work I've done, so I haven't been so sure on how it works