All Stream Types and I/O Facilities

All Stream Types and I/O Facilities

A compact scan page for standard stream objects, stream classes, string/file streams, and related I/O building blocks.

How to use this reference page

Use reference pages to confirm names, categories, nearby facilities, and the constraints that matter before writing or reviewing code.

Scan the top of the page first to identify the primary types, functions, or algorithm families involved.
Use the nearby-page links when your question is really about a companion header, related algorithm family, or broader subsystem.
Validate tricky behavior with a small compileable example before relying on memory for details like invalidation, ordering, allocation, or lifetime rules.

All Stream Types and I/O Facilities

Standard stream objects

std::cin
std::cout
std::cerr
std::clog
wide counterparts such as std::wcin, std::wcout, std::wcerr, std::wclog

Core stream class families

std::istream
std::ostream
std::iostream
std::streambuf
std::ios_base

File and string streams

std::ifstream
std::ofstream
std::fstream
std::istringstream
std::ostringstream
std::stringstream

Common I/O helpers

manipulators such as std::boolalpha, std::hex, std::setw, std::setprecision
state flags such as goodbit, failbit, badbit, eofbit
extraction/insertion operators and locale-aware formatting behavior

Practical rules

Check stream state after formatted extraction when input may be malformed.
Prefer std::format or std::print when formatting complexity grows beyond simple insertion chains.
Use string streams sparingly in hot paths due to allocation and locale overhead.

Example in practice

#include <sstream>
#include <string>

int main() {
    std::istringstream input{"17 debug"};
    int level{};
    std::string tag;
    input >> level >> tag;
    return level == 17 && tag == "debug" ? 0 : 1;
}