hassaananjum

#include <string.h>
#include <bitset>
#include <iostream>

std::string hex_to_binary(std::string hexstring){
  static char base16encoding_table[] = {'0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f'};
  std::string binstring;
  for( int i = 0; i < hexstring.length(); i++){
    binstring += std::bitset<4>((int)(strchr(base16encoding_table,hexstring[i]) - base16encoding_table)).to_string();
  }