C++程序  |  26行  |  604 B

//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// <iostream>

// istream cerr;

#include <iostream>
#include <cassert>

int main()
{
#if 0
    std::cerr << "Hello World!\n";
#else
    assert(std::cerr.tie() == &std::cout);
    assert(std::cerr.flags() & std::ios_base::unitbuf);
#endif  // 0
}