透明地操作插入到Ostream中的字符串

streambuf

ostream rdbuf

aes_ctr_streambuf encrypter(key);
zlib_streambuf compressor;
::std::cout << stack_streambuf(encrypter) << stack_streambuf(compressor);

I/O stream Jonathan Turkanis CodeRage, LLC Boost.Iostreams

second example

#include <iostream>
#include <iomanip>

int main(int, char**)
{
  int a = 10;
  std::cout << "a: " << a << std::endl; //outputs: "a: 10"
  std::cout << "a: " << std::hex << a << std::endl; //outputs: "a: a"
  std::cout << "a: " << std::dec << a << std::endl; //outputs: "a: 10"

  return EXIT_SUCCESS;
}