Display the binary representation of a number in C

Question

Possible Duplicate    Is there a printf converter to print in binary format        Still learning C and I was wondering    Given a number  is it possible to do something like the following   char a   5  printf  binary representation of a    b  a    gt  101   Or would i have to write my own method to do the transformation to binary

User · Answer

There is no direct format specifier for this in the C language. Although I wrote this quick python snippet to help you understand the process step by step to roll your own.

#!/usr/bin/python

dec = input("Enter a decimal number to convert: ")
base = 2
solution = ""

while dec >= base:
    solution = str(dec%base) + solution
    dec = dec/base
if dec > 0:
    solution = str(dec) + solution

print solution

Explained:

dec = input("Enter a decimal number to convert: ") - prompt the user for numerical input (there are multiple ways to do this in C via scanf for example)

base = 2 - specify our base is 2 (binary)

solution = "" - create an empty string in which we will concatenate our solution

while dec >= base: - while our number is bigger than the base entered

solution = str(dec%base) + solution - get the modulus of the number to the base, and add it to the beginning of our string (we must add numbers right to left using division and remainder method). the str() function converts the result of the operation to a string. You cannot concatenate integers with strings in python without a type conversion.

dec = dec/base - divide the decimal number by the base in preperation to take the next modulo

if dec > 0: solution = str(dec) + solution - if anything is left over, add it to the beginning (this will be 1, if anything)

print solution - print the final number

User · Answer

Use a lookup table  like   char  table 16      0000    0001         1111      then print each nibble like this  printf   s s   table a   0x10   table a   0x10      Surely you can use just one table  but it will be marginally faster and too big

User · Answer

This code should handle your needs up to 64 bits     char  pBinFill long int x char  so  char fillChar      version with fill char  pBin long int x  char  so                         version without fill   35 define width 64  char  pBin long int x char  so     char s width 1    int    i width   s i--  0x00       terminate string  do       fill in array from right to left   s i--   x   1     1   0       determine bit   x gt  gt  1      shift right 1 bit    while  x  gt 0    i         point to last valid character  sprintf so   s  s i      stick it in the temp string string  return so       char  pBinFill long int x char  so  char fillChar       fill in array from right to left  char s width 1    int    i width   s i--  0x00       terminate string  do      s i--   x   1     1   0     x gt  gt  1      shift right 1 bit    while  x  gt  0    while i gt  0  s i--  fillChar        fill with fillChar   sprintf so   s  s    return so       void test      char so width 1      working buffer for pBin  long int   val 1   do       printf   ld   t t  lx   t t0b s n  val val pBinFill val so 0       val  11     generate test data    while  val  lt  100000000      Output  00000001   0x000001     0b00000000000000000000000000000001 00000011   0x00000b     0b00000000000000000000000000001011 00000121   0x000079     0b00000000000000000000000001111001 00001331   0x000533     0b00000000000000000000010100110011 00014641   0x003931     0b00000000000000000011100100110001 00161051   0x02751b     0b00000000000000100111010100011011 01771561   0x1b0829     0b00000000000110110000100000101001 19487171   0x12959c3    0b00000001001010010101100111000011

User · Answer

You have to write your own transformation  Only decimal  hex and octal numbers are supported with format specifiers

User · Answer

Yes  write your own   something like the following complete function    include  lt stdio h gt     only needed for the printf   in main        include  lt string h gt      Create a string of binary digits based on the input value     Input         val   value to convert         buff  buffer to write to must be  gt   sz 1 chars         sz    size of buffer     Returns address of string or NULL if not enough space provided     static char  binrep  unsigned int val  char  buff  int sz        char  pbuff   buff          Must be able to store one character at least         if  sz  lt  1  return NULL          Special case for zero to ensure some output         if  val    0             pbuff      0            pbuff     0           return buff                Work from the end of the buffer back         pbuff    sz       pbuff--     0           For each bit  going backwards  store character         while  val    0            if  sz--    0  return NULL           pbuff--     val  amp  1     1     1     0               Get next bit             val  gt  gt   1            return pbuff 1      Add this main to the end of it to see it in operation    define SZ 32 int main int argc  char  argv          int i      int n      char buff SZ 1           Process all arguments  outputting their binary         for  i   1  i  lt  argc  i              n   atoi  argv i            printf    3d   9d - gt   s  from   s   n   i  n              binrep n buff SZ   argv i               return 0      Run it with  progname 0 7 12 52 123  to get      1          0 - gt  0  from  0      2          7 - gt  111  from  7      3         12 - gt  1100  from  12      4         52 - gt  110100  from  52      5        123 - gt  1111011  from  123

User · Answer

There is no direct way  i e  using printf or another standard library function  to print it  You will have to write your own function      This code has an obvious bug and another non-obvious one       void printbits unsigned char v       for    v  v  gt  gt   1  putchar  0     v  amp  1        If you re using terminal  you can use control codes to print out bytes in natural order   void printbits unsigned char v        printf    s    int ceil log2 v     1            for    v  v  gt  gt   1  printf   x1b 2D c   0     v  amp  1

User · Answer

Based on dirkgently s answer  but fixing his two bugs  and always printing a fixed number of digits   void printbits unsigned char v      int i     for C89 compatability   for i   7  i  gt   0  i--  putchar  0      v  gt  gt  i   amp  1

User · Answer

include lt iostream gt   include lt conio h gt   include lt stdlib h gt  using namespace std  void displayBinary int n           char bistr 1000          itoa n bistr 2           2 means binary u can convert n upto base 36        printf   s  bistr       int main         int n      cin gt  gt n      displayBinary n       getch        return 0

[c] Display the binary representation of a number in C?

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