How to add parity bits on c#

Question

Please help I want c# to come up with this once it comes up

Please enter a 7-bit binary number:

Your number with a parity bit is:

00100111

This is my code that I have come up with, its probably wrong please can you correct it so it is alright?

{
   Console.WriteLine("Please enter a 7- bit binary number");

   string number = Console.ReadLine();

   int count1 = 0;
   int count2 = 0;

   for(int i = 0; i < number.Length; i++)
   {
      count1++;
   }
   else 
   {
       count2++;
   }

   if (count1 < count2) 
      Console.WriteLine("Your number with parity bit is "+ number+ "1");
}
else
{ 
    Console.WriteLine("Your number with parity bit is "+ number + "0");
}

    }
}

}

Thx in advance for the help

{ Console.WriteLine("Please enter a 7- bit binary number"); string number=Console.ReadLine(); int count1=0; int count2=0; for(int i=0;i — user1726553, Feb 11 '13 at 17:21
Use the "Code Sample" button on the toolbar (5th button along). — Christian Hayter, Feb 11 '13 at 17:24
That is not valid code. Please make sure it at least compiles. You also do not seem to understand what parity is; `count1 — poke, Feb 11 '13 at 17:25
I've never before seen a `for (....) {}` loop with an `else { -...} ` clause - what is this supposed to be?? Is this your **REAL** code?? I can't imagine this would even **compile** ..... — marc_s, Feb 11 '13 at 17:26
Well that was what i thought would work but i guess i am wrong could u help? — user1726553, Feb 11 '13 at 17:28
@user1726553 The number of zeros in the binary representation is not relevant to the parity—the number of ones is. Your check if `count1 < count2` is not able to check that really; but that’s also pretty hard to justify, given that you probably forgot to include the condition for the missing if that counts up those variables (I’d still guess that it’s wrong). — poke, Feb 11 '13 at 17:29
it doesn't work could u help me correct it and get rid of everything i have done wronh — user1726553, Feb 11 '13 at 17:30
Where should we start? Where did you get that "code" from? Maybe you should start with the basics of C#. — jAC, Feb 11 '13 at 17:33

score 1 · Accepted Answer · answered Feb 11 '13 at 17:31

1

This should do it:

Console.WriteLine("Please enter a 7- bit binary number");

string number = Console.ReadLine();

int count = 0;

for(int i = 0; i < number.Length; i++)
{
   if(number[i] == '1')
   {
      count++;
   }
}

Console.WriteLine("Your number with parity bit is "+ number + (count % 2).ToString());

I'd imagine this is beyond your current level, but this should also work:

Console.WriteLine("Please enter a 7- bit binary number");

string number = Console.ReadLine();

string parityBit = (number.Where(c => c == '1').Count() % 2).ToString();

Console.WriteLine("Your number with parity bit is "+ number + parityBit);

answered Feb 11 '13 at 17:31

JLRishe

99,490
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Thx so much i gave u a tick – user1726553 Feb 11 '13 at 17:36
What about this user input: "123456"? Why to avoid conversion to int, processing (working with integer representation) and conversion to string stages? – Sergey Vyacheslavovich Brunov Feb 11 '13 at 18:16

score 1 · Answer 2 · answered Feb 11 '13 at 17:35

1

So, the parity bit indicates whether or not the input has an even number of one-bits. So if your input string is in binary (which you normally shouldn’t safely assume, but we’ll ignore that for now), you need to simply count the number of 1s in the binary string.

Following your initial idea (I think?), you could do it like this:

int numberOfOnes = 0;
for (int i = 0; i < bitstring.length; i++)
{
    if (bitstring[i] == '1')
        numberOfOnes++;
}

if (numbersOfOnes % 2 == 0)
    // even number of ones
else
    // uneven number of ones

Note that there are two different versions of the parity bit, depending on if you have a 1 if the parity is even, or a 0 if the parity is even. Which you choose is up to you.

answered Feb 11 '13 at 17:35

poke

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Consider the following user input: "123456". The logic does not validate user input. – Sergey Vyacheslavovich Brunov Feb 11 '13 at 18:19
@SergeyBrunov I said that in the first paragraph. – poke Feb 11 '13 at 19:21
@poke, so I think there is no need to develop the idea because **it is not safe**. Why not convert the input to integer representation, process it and print output? – Sergey Vyacheslavovich Brunov Feb 12 '13 at 06:04
@SergeyBrunov I consider StackOverflow to be about *learning* in the first place; not something you can throw some random code into and get perfect and safe code back. I think it is important to first pursue OP’s own idea so he understands what he did wrong there, before providing a completely different—and likely more complex—one. Also I don’t consider the parse-to-int way better as you may not always have the full bit representation available (it’s like that on the hardware). Simply checking for invalid characters as you go is way easier (there are only two valid characters after all). – poke Feb 12 '13 at 10:04
@poke, completely agree with you about the concept of StackOverflow. – Sergey Vyacheslavovich Brunov Feb 12 '13 at 10:19

score 1 · Answer 3 · answered Feb 11 '13 at 17:51

The algorithm:

Convert the string to integer.
Find the parity bit value.
"Append" parity bit value to the source integer => the result integer.
Convert the result integer to string and write the string to output.

Source code:

Console.Write("Please enter a 7-bit binary number: ");
string numberString = Console.ReadLine();

// Convert to integer representation.
int number = Convert.ToInt32(numberString, 2);

// Find parity bit value for the integer.
bool parity = false;
int tempNumber = number;
while (tempNumber > 0)
{
    parity ^= tempNumber % 2 != 0;
    tempNumber >>= 1;
}

// "Append" parity bit.
int numberWithParity = number << 1 | (parity ? 1 : 0);

// Convert the result to string representation.
numberString = Convert.ToString(numberWithParity, 2).PadLeft(8, '0');
Console.WriteLine("Your number with parity bit is {0}", numberString);

How to add parity bits on c#

3 Answers3