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

/*
  take input
  decide if hex or binary
  then convert
  then print

  let's convert binary to hex first
  for each byte, split into nibble,

*/


//might have to add some padding, but basic works
void bintohex(char* string_in){
  const char hexmap[] = "0123456789ABCDEF";
  char hexnum[4];
  int stringl = strnlen(string_in, 10)-1;
  //aantal nibbles
  int loopamount = stringl/4;
  printf("totalstringlength=%d\n", stringl);
  for (int loopcount = 0; loopcount < loopamount; loopcount++) {
	int bin2dec = 0;
	//rechts naar links in nibble
	for (int nibbledigit = 0 ; nibbledigit <4 ; nibbledigit++) {
	  //nibblecount + current
	  int targetdigit = loopcount*4+(4-1-nibbledigit);
	  //check if j+i = 1
	  //printf("nibbledigit:%d=%c=%i\n", j, string_in[targetdigit],1<<j);
	  bin2dec += 1 * (string_in[targetdigit]-'0')*1<<(nibbledigit);
	}
	hexnum[loopcount]=hexmap[bin2dec];
	printf("nibble:%i=%d\n",loopcount,bin2dec);
  }
  printf("hex=%s", hexnum);
}

int main(){
  printf("input either binary or hexadecimal\n");
  char buff[32+2]; //4bytes+\n+null
  fgets(buff, sizeof(buff), stdin);
  bintohex(buff);
}