iostream

I've always wondered why the C++ Standard library has instantiated basic_[io]stream and all its variants using the char type instead of the unsigned char type. char means (depending on whether it is signed or not) you can have overflow and underflow for operations like get(), which will lead to implementation-defined value of the variables involved. Another example is when you want to output a byte, unformatted, to an ostream using its put function. Any ideas? Note : I'm still not really convinced. So if you know the definitive answer, you can still post it indeed. Possibly I've misunderstood

What's the <iosfwd> header used for? Why is it necessary? Any example? It's so you can declare, in your own headers, methods that rely on the declarations of iostream types without having to #include the iostream headers themselves, which are large, complex and slow to compile against. Here's a simple example: // foo.h #include <iosfwd> void sucker(std::iostream& is); // foo.cc #include <iostream> void sucker(std::iostream& is) { is >> somevar; } Adam Rosenfield As @Marcelo Cantos mentioned, it's so you can include the declaration of iostream classes and functions without including the full

I usually use stringstream to write into in-memory string. Is there a way to write to a char buffer in binary mode? Consider the following code: stringstream s; s << 1 << 2 << 3; const char* ch = s.str().c_str(); The memory at ch will look like this: 0x313233 - the ASCII codes of the characters 1, 2 and 3. I'm looking for a way to write the binary values themselves. That is, I want 0x010203 in the memory. The problem is that I want to be able to write a function void f(ostream& os) { os << 1 << 2 << 3; } And decide outside what kind of stream to use. Something like this: mycharstream c; c << 1

Inspired by my previous question A common mistake for new C++ programmers is to read from a file with something along the lines of: std::ifstream file("foo.txt"); std::string line; while (!file.eof()) { file >> line; // Do something with line } They will often report that the last line of the file was read twice. The common explanation for this problem (one that I have given before) goes something like: The extraction will only set the EOF bit on the stream if you attempt to extract the end-of-file, not if your extraction just stops at the end-of-file. file.eof() will only tell you if the

That is the point. How to write and read binary files with std::vector inside them? I was thinking something like: //============ WRITING A VECTOR INTO A FILE ================ const int DIM = 6; int array[DIM] = {1,2,3,4,5,6}; std::vector<int> myVector(array, array + DIM); ofstream FILE(Path, ios::out | ofstream::binary); FILE.write(reinterpret_cast<const char *>(&myVector), sizeof(vector) * 6); //=========================================================== But I don't know how to read this vector. Because I thought that the following was correctly but it isn't: ifstream FILE(Path, ios::in |