C - convert char or int to binary string and append to char array

Question

I have an array of char containing binary string, let's call it binString. I also have another array of character that has a few characters, let's call it asciiString. I want to convert each asciiString character to binary string.

For instance, binString will have: "00001101". And asciiString will be: "ba". Now I want to convert b to binary which is "01100010" and append to binString. Also convert char 'a' to bin and do the same. If there is a character like "2", first need to convert to int, then convert to bin, so "2" should result in "00000010".

Here is my code so far:

 char *asciiToBin(int value, int bitsCount)
 {
         char *output[16];
         int i;
         output[bitsCount - 1] = '\0';
         for (i = bitsCount - 1; i >= 0; --i, value >>= 1)
         {
            output[i] = (value & 1) + '0';
         }
         return output;
 }

Now, from another function:

position = 8; // this is filled up to this character
char *binString[32];
len = 16;
bin16 = asciiToBin(atoi(operand), len);
for (int x = 0; x < len; x++)
{
    char c = bin16[x];
    binString[position + x + 1] = c;
}

Can someone help please?

Thanks,

the code above doesn't work. I am not sure what is the issue. Also I think I should not use array pointers? alternatives? — user3530178
– user3530178, Commented Apr 14, 2014 at 0:58
Note: Avoid magic numbers like 32 or 16. Suggest len = sizeof(int)*CHAR_BIT + 1; — chux
– chux, Commented Apr 14, 2014 at 4:31

BLUEPIXY · Accepted Answer · 2014-04-14 10:50:35Z

0

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

char *asciiToBin(unsigned char value){
    static char output[CHAR_BIT+1];
    int i;
    for(i = CHAR_BIT -1; i>= 0;--i, value >>= 1){
        output[i] = "01"[value & 1];
    }
    return output;
}

char *convBinAndCat(char *d, const char *s){
    char *out = strchr(d, '\0');
    for(;*s;++s){
    //  unsigned char value = isdigit(*s) ? *s - '0' : *s;
        unsigned char value = isdigit(*s) ? strcspn("0123456789", (char[]){ *s, '\0'}) : *s;
        strcpy(out, asciiToBin(value));
        out += CHAR_BIT;
    }
    return d;
}

int main(){
    char binString[CHAR_BIT*4 + 1] = "00001101";
    printf("%s\n", convBinAndCat(binString, "ba2"));//00001101011000100110000100000010
    return 0;
}

answered Apr 14, 2014 at 10:50

BLUEPIXY

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Comments

Mahonri Moriancumer · Accepted Answer · 2014-04-14 01:23:04Z

0

My attempt to clean-up:

int asciiToBin(int value, int bitsCount, char *output)
  {
  int i = bitsCount - 1;

  output[i] = '\0';
  for(; i >= 0; --i, value >>= 1)
     output[i] = (value & 1) ? '1' : '0';

  return(0);
  }

My attempt to boil-down the rest... but I have to admit failure. I guess it would be helpful to know more about the goal...

int   position = 8; // this is filled up to this character
char *binString[32];
int   len = 16;
char  bin16[len+1];

asciiToBin(atoi(operand), len, bin16);

for(int x = 0; x < len; x++)
    binString[position + x + 1] = bin16[x];

answered Apr 14, 2014 at 1:23

Mahonri Moriancumer

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