从istream到ostream的快速受控拷贝

你能用0x吗?如果是,则可以使用copy:

copy_n( istreambuf_iterator<char>(myistream),
        100,
        ostreambuf_iterator<char>(myostream)
);

编辑1:

void stream_copy_n(std::istream & in, std::size_t count, std::ostream & out)
{
    const std::size_t buffer_size = 4096;
    char buffer[buffer_size];
    while(count > buffer_size)
    {
        in.read(buffer, buffer_size);
        out.write(buffer, buffer_size);
        count -= buffer_size;
    }

    in.read(buffer, count);
    out.write(buffer, count);
}