C function to convert hexadecimal number to string. I was looking for it for the kernel I'm trying to make but couldn't find it, so wrote one myself. Hope this helps somebody.

hex_to_str.c

char checkTheBits(unsigned char hByte);

char* hex_to_string(unsigned int n){
  // output hexadecimal chars
	
	unsigned char* location = &n; //get the location of the hex number
	char value[9] = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}; // init null byte array
								                                                 // array has 9 values, because last one reserved fur null terminator
	unsigned char temp_char_l, temp_char_h; // temporary vars
	int i = 0, j = 7; // start at 7, because tested on little endian machine
	while(location[i]){
			
		// get lower 4 bits
		temp_char_l = location[i] & 0x0f;
		if(!(value[j--] = checkTheBits(temp_char_l))) break; // shouldn't happen if hex number given
		
		// get upper 4 bits
		temp_char_h = location[i++] >> 4;
		if(!(value[j--] = checkTheBits(temp_char_h))) break; // shouldn't happen if hex number given
		
		if ( i == 4 || j <= 0) break;
	}
	// readjust the array, since we start at the end of the array because of the endianness
	j = 0;
	while(!j){
		if (!value[j]){
			for(i = 0; i < 8; i++){
				value[i] = value[i+1];
			}
		} else { break;}
	}	
	return value;
}
char checkTheBits(u8int hByte){
	/*
	  Might not be the most efficient algorithm to find the hex
	  value, but that's the way I thought to do it
	*/

	// check and print the half byte value
	switch(bit){
		case 0x01:
			return '1';
		case 0x02:
			return '2';
		case 0x03:
			return '3';
		case 0x04:
			return '4';
		case 0x05:
			return '5';
		case 0x06:
			return '6';
		case 0x07:
			return '7';
		case 0x08:
			return '8';
		case 0x09:
			return '9';
		case 0x0A:
			return 'A';
		case 0x0B:
			return 'B';
		case 0x0C:
			return 'C';
		case 0x0D:
			return 'D';
		case 0x0E:
			return 'E';
		case 0x0F:
			return 'F';
		case 0x00:
			return '0';
		default:
			// should never happen
			return 0;
	}
}