How to convert char to an array of bits in c++?

Question

I need to get each Character of a string as a sequence of bits either in an array or just traverse over it in a loop, either way works. This is something I used to do in ASM way back, and am not sure how that can be done in c++.

EDIT: I am trying to replicate what I did sometime back with asm, reading a file in memory and traversing it bit by bit, manipulate each bit, do some more cyphering and save it back.

Basically a simple Encryption. Its not a homework neither it is a project.

@user93353 nothing :) Don't have slightest of idea how to go about it. — StudentX
– StudentX, Commented Dec 11, 2012 at 16:03
@user93353: Perhaps, but I doubt it, and even if it were homework, officially that's OK. You can choose not to answer homework questions, but people are not forbidden from asking them. In any case, it's irrelevant if this is homework. StudentX is posing an XY problem, where they are trying to accomplish X by doing Y and asking how to do Y, where the interesting question is "what is X?" — John Dibling
– John Dibling, Commented Dec 11, 2012 at 16:24
@user93353: I agree with your link, but it bears no relation to any reason why you would have replied with the comment, "Homework, possibly." — John Dibling
– John Dibling, Commented Dec 11, 2012 at 16:32

Nemanja Boric · Accepted Answer · 2012-12-11 16:02:47Z

6

You can iterate through it using bit operators:

unsigned char c = 'a'
for(int i = 0; i < 8; i++)
{
  std::cout << (c >> i) & 1 << std::endl;
}

This will shift c to the right for i position, and use bitwise AND to get value of the least significant bit.

answered Dec 11, 2012 at 16:02

Nemanja Boric

22.2k6 gold badges72 silver badges93 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Gorpik · Accepted Answer · 2012-12-11 16:01:38Z

6

The Standard Library has a class for that, std::bitset. It may be what you need.

answered Dec 11, 2012 at 16:01

Gorpik

11.1k5 gold badges39 silver badges58 bronze badges

Comments

MartyE · Accepted Answer · 2012-12-11 16:01:01Z

2

You'll want to look using a bit-mask and bit-wise operators &, |, >> and/or maybe <<. I'm guessing that you'll want to store them in an array of bool type, something like bool bitArray[256];

Of course it is standard practice to just use unsigned char for storing a bunch of bits.

answered Dec 11, 2012 at 16:01

MartyE

6663 silver badges7 bronze badges

Comments

Olaf Dietsche · Accepted Answer · 2012-12-11 16:07:29Z

2

You can just loop over the character and check the bits with a bitmask

char c;
for (int i = 0; i < 8; ++i) {
    bool is_set = c & (1 << i);
    std::out << "Bit " << i << ": " << is_set << '\n';
}

or a string

std::string s;
for (auto p = s.begin(); p != s.end(); ++p) {
    char c = *p;
    // loop over the bits
}

answered Dec 11, 2012 at 16:07

Olaf Dietsche

74.4k9 gold badges113 silver badges214 bronze badges

Collectives™ on Stack Overflow

How to convert char to an array of bits in c++?

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related