Converting an integer to binary in C

Question

I\'m trying to convert an integer 10 into the binary number 1010.

This code attempts it, but I get a segfault on the strcat():

int int_to_bin(int k)
{
          


        

Answer 1

You can use function this function to return char* with string representation of the integer:

   char* itob(int i) {
      static char bits[8] = {'0','0','0','0','0','0','0','0'};
      int bits_index = 7;
      while ( i > 0 ) {
         bits[bits_index--] = (i & 1) + '0';
         i = ( i >> 1);
      }
      return bits;
   }

It's not a perfect implementation, but if you test with a simple printf("%s", itob(170)), you'll get 01010101 as I recall 170 was. Add atoi(itob(170)) and you'll get the integer but it's definitely not 170 in integer value.