Solved

Conversion Binary <-> Decimal

Posted on 2002-04-12
7
83,257 Views
Last Modified: 2013-11-15
Hi
I need two simple functions:

1 - Convert Binary to Decimal and returns this value
2-  Convert Decimal to Binary and returns this value

Thanks
0
Comment
Question by:maomorta
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
7 Comments
 
LVL 2

Expert Comment

by:jonnin
ID: 6936650
dec to bin:
what I do is make a hex lookup table

0 = "0000"
1 = "0001"
...
f = "1111"

and do an sprintf into a hex string.
int i, char * str...
sprintf(str, "%x", i);

then each hex digit is replaced with the
lookup value. Kill leading zeros if you want too...

bin to dec is easier
place the bits into an unsigned int  using shift operator
<< ...


0
 
LVL 2

Accepted Solution

by:
jonnin earned 100 total points
ID: 6936656
come to think of it, you can shift the bits out instead of the sprintf thing...
0
 
LVL 6

Expert Comment

by:Triskelion
ID: 6936954
// Binary to Decimal
http://www.c-for-dummies.com/lessons/bonus/13/

// Decimal to Binary
http://mathforum.com/dr.math/problems/kaufman.10.26.99.html

I will try to make an example.
0
Ransomware-A Revenue Bonanza for Service Providers

Ransomware – malware that gets on your customers’ computers, encrypts their data, and extorts a hefty ransom for the decryption keys – is a surging new threat.  The purpose of this eBook is to educate the reader about ransomware attacks.

 
LVL 6

Expert Comment

by:Triskelion
ID: 6937577
// Cheap example.  Microsoft compiler
#include <stdio.h>
#include <stdlib.h>
#include <string.h>


long     BinaryToDecimal(const char * pstrBinary)
{
     int     intLoop=0;
     long     lngReturn=0L;
     long     lngMultip=1L;
     for (intLoop=0; intLoop < (int)strlen(pstrBinary); intLoop++)
          {
          if ('1' == pstrBinary[intLoop])
               {
               lngReturn += lngMultip;
               }
          lngMultip *= 2;
          }
     return     lngReturn;
}


char     *     DecimalToBinary(long lngDecimal)
{
     static     char strReturn[128]={0};
     _ltoa(lngDecimal, strReturn, 2);
     return strReturn;
}


int main(void)
{
     long          lngDecimal     =     7;
     char     *     pstrBinary     =     "111";


     printf("B2D=%ld\nD2B=%s\n",     BinaryToDecimal(pstrBinary),     DecimalToBinary(lngDecimal));
}
0
 

Author Comment

by:maomorta
ID: 6938278
Hi jonnin,
As you sugested I wrote this program but I have a segmentation fault, and I can not understand where the problem is.

Can you give more details about
"bin to dec is easier
place the bits into an unsigned int  using shift operator
<< ..."

#include <stdio.h>
#include <string.h>

void int2bin(long num);

int main()
{    
     int2bin(12343);    
}


void int2bin(long num)
{
     char *hex;
     char bin[50]="";
     sprintf(hex, "%X", num);              
     while (*hex) {
          switch (*hex)
            {
                     case '0':
                             strcat(bin, "0000");                
                break;          
              case '1':
                   strcat(bin, "0001");                
                break;          
              case '2':
                   strcat(bin, "0010");
                break;
              case '3':
                   strcat(bin, "0011");
                break;
              case '4':
                   strcat(bin, "0100");
                break;
              case '5':
                   strcat(bin, "0101");
                break;
              case '6':
                   strcat(bin, "0110");
                break;
              case '7':
                   strcat(bin, "0111");
                break;
              case '8':
                   strcat(bin, "1000");
                break;
              case '9':
                   strcat(bin, "1001");
                break;
              case 'A':
                   strcat(bin, "1010");
                break;
              case 'B':
                   strcat(bin, "1011");
                break;
              case 'C':
                   strcat(bin, "1100");
                break;
              case 'D':
                   strcat(bin, "1101");
                break;
              case 'E':
                   strcat(bin, "1110");
                break;
              case 'F':
                   strcat(bin, "1111");
                break;                                
          }
                                                 
          *hex++;
     }
     
     printf("%s\n", bin);          
                         
}
0
 
LVL 1

Expert Comment

by:Shivshankar
ID: 6938532
Make these changes...

char * hex; ----> to  
    char * hex = (char *)(malloc(sizeof(long)*2*sizeof(char)));
Also, add this as a better programming practice.
    char *start_addr = hex;

*hex++;   -----> to
   hex++; //Just hex++

At the end of the code:
  free(start_addr);
0
 
LVL 18

Expert Comment

by:deighton
ID: 6942302
char *int2bin(long lno,char *buf)
{
     int c = 32;
     


     buf[32]=0;
     do
     {
         
          buf[--c] = '0' + (lno & 1);
          lno = lno >> 1;
     }
     while (c);
     

     return buf;

}    


long bin2int(char *buf)
{
     long val=0;
     int c=0;


     while (buf[c])
     {
          val = (val << 1) | (buf[c++]-'0');
     }
         
     return val;

}


'example

printf("\n%s",int2bin(1024,test));
printf("\n%li",bin2int(test));

0

Featured Post

How our DevOps Teams Maximize Uptime

Our Dev teams are like yours. They’re continually cranking out code for new features/bugs fixes, testing, deploying, responding to production monitoring events and more. It’s complex. So, we thought you’d like to see what’s working for us. Read the use case whitepaper.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Today, still in the boom of Apple, PC's and products, nearly 50% of the computer users use Windows as graphical operating systems. If you are among those users who love windows, but are grappling to keep the system's hard drive optimized, then you s…
All of the resources available today make learning a new digital media easier than ever-- if you know where to begin. This is a clear, simple guide to a few of the basic digital art mediums and how to begin learning them on your own.
The viewer will learn how to successfully download and install the SARDU utility on Windows 8, without downloading adware.
An overview on how to enroll an hourly employee into the employee database and how to give them access into the clock in terminal.

688 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