bit level access using C++

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Is it possible to access each bit in a byte using C++. For example if i have

char * a = NULL;
a = new char[500];

or

char a[500];

Like how one accesses each individual element using its index , is there any similar method to access each bit in C++.

Please mention a method if feasible in C++ and also the difference between accessing those bits in the pointer method and in the normal array initialization method.

Is it possible to realise a linear string in 2 dimensional matrix form using these combination of bits.

Posted 12-May-13 23:55pm

compuknow

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Graham Breach 13-May-13 6:02am

This smells like homework.

1 solution

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CPallini · Answer 1 · 2013-05-13T00:07:00

Solution 1

Suppose, for generality:

C++

const int  N = 500;
a = new char[N];
char b[N];

You access bit bitno of either a or b in the same way (note: not tested):

C++

int getbit(int bitno, int x[], int size)
{
  if ( bitno < 0 || bitno >= (size*8) )
  {
    // throw an exception here
  }
  int byte, b;
  byte = bitno / 8;
  b = bitno % 8
  return (x[byte] >> b) & 0x01;
}

Posted 13-May-13 0:07am

CPallini

Comments

Sergey Alexandrovich Kryukov 5-Jun-13 23:12pm

Looks right; even if something a bit off, it's easy to fix by thinking just a bit. My 101. :-)
—SA

CPallini 6-Jun-13 1:49am

:-)