c - Trimming a string of Int -

in program want input string of integer e.g 2107900000. want length , want remove 0's , 1's.

perhaps not optimal, copy buffer conditionally:

 char buffer[20];  char num[] = "2107900000";  int j = 0;  (int = 0; num[i]; i++)  {    if (num[i] != '0' && num[i] != '1')    {      buffer[j] = num[i];      j++;    }  }  buffer[j] = 0 //null terminator 

or in single buffer:

 char num[] = "2107900000";  int j = 0;  (int = 0; num[i]; i++)  {    if (num[i] != '0' && num[i] != '1')    {      num[j] = num[i];      j++;    }  }  num[j] = 0 //null terminator