How to create my own stream buffer

[tonnot]

I have spent all the day but I'm unable to create a stream buffer and 'play' with it.
I want to have a i-o stream based on a known size buffer.
Later I want to put and get data, like if it was a file, but it isn't a file.
Please, can anybody help me?

Where to start ? Cplusplus reference is a good place but I dont see how to begin...
Thanks

[joh024]

I think you just mean that you want to overload the stream operators. If that's the case, then you would start with operator overloading.

EDIT: HEre is a good overview -> http://faculty.cs.niu.edu/~mcmahon/CS241/Notes/extraction.html

[Computergeek01]

Any reason a Vector wouldn't work for you? I can understand if you want to do it this way for educational purposes though.

[tonnot]

I want to put and get data into a buffer, can I do it with vectors?
My 'data' can have any kind of data types...
Thanks

[Computergeek01]

The vector would be a dynamically sized array that you could asign to any one data type per vector.

[tonnot]

Hello computergeek.
I wish you help me.
My questions about this theme (buffers, streams, etc) are related around this problem:
I want to 'play' with data, fill my char [] buffer and then write/read form disk.

How can I use this char[] buffer like a file ? That is to say, I want to use seek, put,get,>>,<<, etc.

If I have this char[] buffer, is there a way to use as 'stream' ? How?
I remember that with Java was easy.

Please, helppppp.... Thanks

[Computergeek01]

You seem to be over complicating things. The beginning of an array is always '0', as for the end of the array I suggest setting it's size with an integer you can reference later. Something like this:

const int X = 10; /*Variable to set the size of the array*/
char array[X];
/* that way later on you can do cool stuff without thinking about the size of your array */
for(int i = 0; i <= X; ++i)
{/*Do something with array[i] */}

See if we had set the size of array to '10' by writing char array[10]; we would have to change it in every place we go threw the array. Now we change 'X' and everything knows the size of 'array[]'.

EDIT: If you used a vector you wouldn't even have to set the size of the array. http://www.cplusplus.com/reference/stl/vector/

[tonnot]

I dont know If all is because my bad english.... (nobody understand my need)

Imagine I have to store a float, 3 doubles, 1 string , and other 2 floats into a char array.
How can I do this ?
This is because I'm praying to find something similar to a 'memorystream'....
Do you understand me now ?
Thanks for your patience

[Computergeek01]

You may have lost me now... Maybe Union? http://www.cplusplus.com/doc/tutorial/other_data_types/#union
But that is a trickey one to learn.

[tonnot]

uff.
I'm going to explain it again.
You know the features of fstream ok?
Well, then I want to have a similar object (a memory stream buffer, if it can be called so) to get and put data, but to-from memory, not to-from disk.

I think the basic iostream can be my object, but I dont know how to create and use it.

My typical work could be:
I write data (any kind of data:1 float, 3 doubles, 1 string, 1 char [], etc ) to my 'buffer'. When it reaches the size I want I save it to a file (or maybe I send to another computer). Then I will read it.
Using Java streams I can do it. Why not with c++
I hope you understand me now.
Thanks

[Duthomhas]

You are looking for a stringstream. That's what we C++ people call our Java MemoryStreams.

[tonnot]

But ... can I use floats, doubles, etc to put-get into stringstream?
An thanks for your two answers...

[Duthomhas]

Yes, the same way you do with normal streams.

#include <iostream>
#include <sstream>
#include <string>
using namespace std;

int main()
  {
  // Demonstrate an inverse variation
  istringstream ss( "9y = 72" );

  double x;
  double k;
  string name;
  string equalsign;

  ss >> x >> name >> equalsign >> k;
  cout << "Given \"" << ss.str() << "\", then " << name << " = " << (k / x) << ".\n";

  return 0;
  }

Hope this helps.