Re: Bit-Pattern of Representation of Objects

From:

"Alf P. Steinbach" <alfps@start.no>

Newsgroups:

comp.lang.c++

Date:

Sun, 16 Jul 2006 15:42:49 +0200

Message-ID:

<4huu2rF1bvjrU1@individual.net>

* Robbie Hatley:

I was struggling to come up with a way to discern the actual
bit patterns of the representations of C++ objects (esp.
objects of small built-in types), and I came up with the
following mess. But I'm wondering, is there an easier way
to do this? This seems so klunky.

#include <iostream>
#include <cmath>
template<typename T>
void Binary(T const & object)
{
size_t size = 8 * sizeof(object); // Size of object in bits.

Use CHAR_BITS or whatever it's called: a byte isn't necessarily 8 bits.

unsigned long long int mask =

C++ does not have a 'long long' type, yet.

static_cast<unsigned long long int>
(pow(2.0, static_cast<double>(size - 1)) + 0.1);

Use left shift operator.

unsigned long long int pattern =
*reinterpret_cast<const unsigned long long int*>(&object);

You don't know that sizeopf(object) <= sizeof(long long).

  for( ; mask > 0 ; mask >>= 1)
  {
    if(pattern & mask) std::cout << "1";
    else std::cout << "0";

std::cout << !!(pattern & mask);

  }
  std::cout << std::endl;
  return;

Unnecessary 'return'.

}

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