I need advices to create a class for a tabulated text multi-types file
Hi all,
I need to create a class to manage such text files :
Here is a use case, say for an existing file like the previous one :
Here is how would be the class :
I really don't know how to manage the arbitrary typing of my columns :
std::vector<std::vector <void *> > &aVectors
std::vector <void *> aVector
Any help would be welcome please.
I need to create a class to manage such text files :
Country Town QtPeople BirthRate France Paris 10000000 0.023 Germany Munchen 6000000 0.012 |
Here is a use case, say for an existing file like the previous one :
|
|
Here is how would be the class :
|
|
I really don't know how to manage the arbitrary typing of my columns :
std::vector<std::vector <void *> > &aVectors
std::vector <void *> aVector
Any help would be welcome please.
Last edited on
You want to keep the rows together, this way you don't need parallel vectors.
|
|
Thanks for your answer LowestOne, but :
1) My question remains open.
2) I need parallel vectors instead of all the raws in a structure, because a)the client uses parallel vectors , b) it does not require pre-definitions of all the structures to be used.
1) My question remains open.
2) I need parallel vectors instead of all the raws in a structure, because a)the client uses parallel vectors , b) it does not require pre-definitions of all the structures to be used.
Last edited on
I am trying something like this :
and get the compilation error :
I thought that reinterpret_cast was not checked by the compiler. How could I do it please ?
|
|
and get the compilation error :
invalid cast from type ‘std::vector<void*>’ to type ‘std::vector<std::basic_string<char> >’ |
I thought that reinterpret_cast was not checked by the compiler. How could I do it please ?
Last edited on
Finaly, I wrote it like this. It works, though I imgine that is not state of the art C++ code - do not hezitate to comment it :
.h
.h
|
|
Last edited on
.cpp
|
|
|
|
use :
result :
|
|
result :
$ cat .table.txt string1 uint2 float3 string u_int32_t float raw1 111 1.1 raw2 222 2.2 raw3 333 3.3 raw4 444 4.4 |
Last edited on
| man wrote: | ||
|---|---|---|
scanf, fscanf, sscanf, vscanf, vsscanf, vfscanf - input format conversion
The scanf() family of functions scans input according to format. This format may contain conversion specifications; the results from such conversions, if any, are stored in the locations pointed to by the pointer arguments that follow format. Each pointer argument must be of a type that is appropriate for the value returned by the corresponding conversion specification. |
|
|
Last edited on
Thanks ne555, but :
As I don't know the order nor the types the client will use a priori.....
| The function expects a sequence of pointers as additional arguments, each one pointing to an object of the type specified by their corresponding %-tag within the format string, in the same order. |
As I don't know the order nor the types the client will use a priori.....
You do know the types and the order.
IIRC you wanted a wrapper for
There was a method with 'variadic templates' that I can't recall, to replace scanf()
|
|
|
|
There was a method with 'variadic templates' that I can't recall, to replace scanf()
Last edited on
| You do know the types and the order. |
No, that's only a test client I wrote. But I don't know what the real clients will do. Some may want just a few columns, some will want to derive new files picking some columns, adding new ones of their own, re-order columns.
To be able to use your class the client needs to create the vectors.
To create the vector it needs to know the types of the columns.
When choosing the columns that he wants, the user needs to know the order. (there could be a problem with repeated columns if he does not know).
So you read the columns specification from the file, and the users tells which ones wants. ¿what info is missing?
To create the vector it needs to know the types of the columns.
When choosing the columns that he wants, the user needs to know the order. (there could be a problem with repeated columns if he does not know).
So you read the columns specification from the file, and the users tells which ones wants. ¿what info is missing?
| So you read the columns specification from the file, and the users tells which ones wants. |
Topic archived. No new replies allowed.