?
Solved

read_bit

Posted on 2001-07-12
2
Medium Priority
?
298 Views
Last Modified: 2008-02-01
Iam have program in C++Builder and I want to read specific bit in String Can I do that and how??
exmple(A=(1000001)bin I want to know the fouth bit is 0 or the last bit is 1)
0
Comment
Question by:aminmohsalih
  • 2
2 Comments
 
LVL 22

Accepted Solution

by:
nietod earned 120 total points
ID: 6277754
You will need to obtain the byte that the bit is stored in, then extract the bit from there with operator &.

example follows.
0
 
LVL 22

Expert Comment

by:nietod
ID: 6277786
Thsi function miight be useful to you

const itn BitPerChr = 8*sizeof(char); // Might need to be changed
                          // for machines that don't store 8 bits per byte.

bool TestStringBit(const char *Str, // string to extract from.
                        int BitNum)   // 0-based bit number of bit to extract.
{
    int BytNum = BitNum / BitPerChr;
    BitNum %= BitPerChr;

   assert(BytNum < strlen(Str)); // Might want this as a permenant test.
   int Byt = Str[BytNum];  // Get desired byte.
   int Msk = 1 << (BitNum-1);  // mask for the desired bit.

   return (Byt & Msk) != 0;
}
0

Featured Post

Free Tool: Site Down Detector

Helpful to verify reports of your own downtime, or to double check a downed website you are trying to access.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Container Orchestration platforms empower organizations to scale their apps at an exceptional rate. This is the reason numerous innovation-driven companies are moving apps to an appropriated datacenter wide platform that empowers them to scale at a …
Article by: evilrix
Looking for a way to avoid searching through large data sets for data that doesn't exist? A Bloom Filter might be what you need. This data structure is a probabilistic filter that allows you to avoid unnecessary searches when you know the data defin…
The goal of the video will be to teach the user the difference and consequence of passing data by value vs passing data by reference in C++. An example of passing data by value as well as an example of passing data by reference will be be given. Bot…
The viewer will be introduced to the member functions push_back and pop_back of the vector class. The video will teach the difference between the two as well as how to use each one along with its functionality.

590 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question