Using classes to retrieve data

[rucafe]

I have a file that contains thousands of numeric entries sorted into four columns. The structure of the data looks something like the following:


3 0.2 0.5 6.2
4 0.1 0.6 6.2 //Track 1
2 0.8 0.5 0.6

2 0.6 0.5 0.4
1 0.8 0.4 2.1 //Track 2
2 0.5 0.4 2.4
4 0.6 0.8 2.5

2 0.3 0.1 0.9 //Track 3
8 0.6 0.8 0.7

The data is grouped into tracks where a new track starts after each line break as shown above (in the actual data there are thousands of tracks). I am trying to write a program that will allow the user to enter a track number. The program will then output the entire track. For example

Track Number: 3
output:
2 0.3 0.1 0.9
8 0.6 0.8 0.7

I need to write the program using classes. I am trying to write a class: class tracks that will contain all of the tracks. The user should be able to call on the class to output the desired track. I am not quite sure how to approach this problem. Any suggestions would be greatly appreciated.

[hamsterman]

Hard time getting a reply, eh? Well, still, don't double post..

Which part do you find problematic? Are you unable to find where a track ends? Are you unable to decide what should be in that class?

[Aikon]

could you do some think like this:

class anyName{
 
         //idea:
         template<int num>
         struct track{
                 double numbers[num][4];

         };

         std::vector<track> allTracks;

}

[hamsterman]

@Aikon, no, you couldn't. In your code track<1> and track<2> are different types and cannot be stored in one vector.

[Aikon]

It's true

but well he could use a vector of vectors of strings

typedef std::vector<std::string> track;

class anyName{


         std::vector< track > allTracks;

};

[zb0S216C]

Considering that the file has thousands of numerical values, it would be smart not to allocate them on the stack, otherwise, you're asking for a stack-overflow. It would be better to dynamically allocate a block of memory to store the extracted data. A vector my be useful. As for the class, I would recommend something like this:

class Track
{
    public:
        double _line[ 3 ][ 4 ];
};

vector < Track > tracks;

I'm not going to tell you how to do it, as it's your assignment, not mine. That code should get you going, at least.

_Wazzak