将aa文本文件转换为二进制stream？

Question

Is this code right?

If this is right, what would be the code for the opposite way like from Binary stream to text?

#include <iostream>
#include <fstream>

int main()
{
   std::ifstream in("in.txt");
   std::ofstream out("out.bin", std::ios::binary);

   double d;
   while(in >> d) {
      out.write((char*)&d, sizeof d);
   }
}

THIS is the input file

A number of issues make the design of the video server, in a video-on-demand application, difficult. First, a video server needs to simultaneously provide video services to multiple clients and guarantee the quality of service for each client. Second, a video server needs to manage system resources, including CPU/disk/memory, and schedule network activity so as to utilize maximally the resources, while not overloading the system. Third, a video server needs to be able to support a variety of VCR operations such as playback, fast-forward, slow-forward, pause, resume, indexing, and scrolling. Finally, a user watching a video may change from one service to another service—for example, from playback to fast-forward or from playback to slow-forward. A video server should support these dynamic service changes while efficiently using system resources.

Answer 1

Yes that is correct. For the opposite, exchange write for read and your are halfway there.

Just note that the encoding of double and it's size might differ on different platforms/systems/compilers, therefore using this type of storage for anything then a temporary stash is not recommended.

Answer 2

Is this code right?

That depends upon what you want it to do. What your program does is to read in a text file consisting entirely of the text representation of rational numbers and white space (eg 1.2 5 99.0 ), and outputs a file consisting entirely of a binary representation of those same numbers.

Note that the details of how those numbers are represented is CPU- OS- and/or compiler-specific.

Is that what you wanted it to do?

what would be the code for the opposite way

The opposite way would be to read in a file consisting of the binary representation of floating-point numbers and output a text file with the text representation of those same numbers. To do that, you would ifstream::read the doubles from an ios::bin file, and >> the numbers to the text file.

Note that the conversion won't be exactly. That is, you will almost certainly not get precisely the same output file as you originally started with, but rather one that is semantically equivalent.

Answer 3

Well, it depends on what you mean by "binary stream". The diference between a file opened in text mode and binary mode is that in binary mode if you read/write a "\r", "\n" or "\r\n" they are read/written literally, whereas in text mode the characters that make up the line end markers on your system are transformed into "\n", see this