Please help me with this program..!!

[tulips]

i am writing a program that reads in a sequence of binary digits 1 or 0 and stores in STL container. The input terminates on any input other than 0 and 1. After finishing the read process applying bit stuffing to the container. In this case bit stuffing occurs after 4 consecutive bits of the same value. Also destuffing code to process the stuffed data and recreate the original data and verify the original data is recovered correctly.


I am not able to run this code. Can someone please help me with it.
i did run the program but the output obtained is specifically not correct.

here is the code i am trying with using string (as STL container) but i am unable to run it due to error.
can u please help me with this code.

#include <iostream>
#include <string>
using namespace std;

int main()
{
    // read bits '0'/'1' into a string; terminate on any other char
    std::string data_stream ;
    char bit ;
    while( std::cin >> bit && ( bit == '0' || bit == '1' ) ) data_stream += bit ;

    // stuff a zero bit after four consecutive bits of the same value.
    std::string stuffed_stream ;
    int cnt = 0 ;
    char bit_last_seen = 0 ;
    int stuff_bits_added = 0 ;
    
    for( bit<=data_stream);           //for each bit in the data_stream
    {
        if( bit==bit_last_seen)       //it is the same as the previous bit
			cnt++;                      

        else // it is a different bit 
        {
            bit_last_seen := this bit ;
            cnt := 1 ; // restart count at 1
        }

        stuffed_stream += bit ; // add the bit 

        if( cnt == 4 ) // there are four consecutive bits of the same value
        {
            stuffed_stream += '0' ; // stuff with a zero bit
            cnt := 0 ; // and reset cnt to zero
            ++stuff_bits_added ; // increment the count of stuff bits added
        }
    }

	std::string destuffed_stream ;
    int cnt = 0 ;
    char bit_last_seen = 0 ;
    int stuff_bits_added = 0 ;
    
    for( bit<=data_stream);           //for each bit in the data_stream
    {
        if( bit==bit_last_seen)       //it is the same as the previous bit
			cnt--;                      

        else // it is a different bit 
        {
            bit_last_seen := this bit ;
            cnt := 1 ; // restart count at 1
        }

        stuffed_stream -= bit ; // sub the bit 

        if( cnt == 4 ) // there are four consecutive bits of the same value
        {
            destuffed_stream += '0' ; // stuff with a zero bit
            cnt := 4 ; // and reset cnt to 4
            --stuff_bits_added ; // decrement the count of stuff bits added
        }
    }
    
    // print out the results  
    std::cout << "     data stream: " << data_stream << '\n'
    std::cout << "  stuffed stream: " << stuffed_stream << '\n'
    std::cout << "stuff bits added: " << stuff_bits_added << '\n' ;
	std::cout << "de-stuff bits added: " << destuffed_stream << '\n' ;
           
}

[tulips]

Please help..!!!!

[Blackavar]

A few things:

First, you should probably read this: http://www.cplusplus.com/forum/beginner/1/. The way you've presented your question strongly discourages people from responding.

Second, I cannot compile your code. My compiler's first error is:
18: error: no match for ‘operator<=’ in ‘bit <= data_stream’

Third, you might want to try http://www.cplusplus.com/forum/beginner/ for this one.

[ats15]

Ouch. What a mess :) You need to address the C++ errors, and logical errors as well.

Works well to line 11
Add ; to lines 66 and 67

Your line 15: how do you know that the character last seen was 0? You should initialize that value to the first value in the data_stream

Line 18: "for( bit<=data_stream); " is not a valid C++ statement. See http://www.cplusplus.com/doc/tutorial/control/ the for loop.

for (initialization; condition; increase) statement;

So you need a counter for position along the data string. Before the for loop declare
size_t position;
the initialization can be position=0, the condition is to be before the end of the string position<data_stream.size() and the increase is position++.
After the for(...) you need to put a statement. The syntax for that is either
for (initialization; condition; increase) statement;
or

for (initialization; condition; increase)
{
 statement1;
 statement2;
 statement3;
}

Please note where you have semicolons.

Further errors: the assignment operator in C++ is "=", not ":="
"this" is a c++ reserved keyword. Do not use it until you are a little bit more advanced.

For the logic of your code, here is the first half (replace this between lines 18 and 38)

    // stuff a zero bit after four consecutive bits of the same value.
    std::string stuffed_stream ;
    int cnt = 0 ;
    char bit_last_seen;
    int stuff_bits_added = 0 ;
    
   
    for( size_t p=0;p<data_stream.size();p++)           //for each bit in the data_stream
    {
      bit=data_stream[p];
      //1st step: copy the bit - you always need to do this step
      stuffed_stream+=bit;
      if(cnt==0) // this condition occurs either at the beginning, or after 4 occurences have been found
      //set the bit_last_seen, increase the cnt to 1, then move to the next bit
      {
        bit_last_seen =bit;
        cnt++; 
      }
      else //do your processing
      {
        if( bit==bit_last_seen)       //it is the same as the previous bit
			  {
			    cnt++;
			  } 
			  else //different bit
			  {
			    bit_last_seen = bit ;
          cnt = 1 ; // restart count at 1
			  }
			  
			  if( cnt == 4 ) // there are four consecutive bits of the same value
        {
            stuffed_stream += '0' ; // stuff with a zero bit
            cnt = 0 ; // and reset cnt to zero
            ++stuff_bits_added ; // increment the count of stuff bits added
        }                   
      }  
    }

i suggest you comment out the rest of your code, except the printing, run the first part, understand the explanations, then write the second part.