Environment

ideone  > C

About

conver 0xFE to "FE" (string)
- used in the serial communication, for example

Example

Hex Encode and Decode in C

I acknowledge his code, but it may cause memory leak by using malloc() without free().
And the free() is used outside at the different location.

Modified Example

I modified the code as following so that malloc() is not needed.

# include <stdio.h>
# include <stdlib.h>
# include <stdbool.h>

// Modified from those in
// https://nachtimwald.com/2017/09/24/hex-encode-and-decode-in-c/
//
bool bin2hex(const unsigned char *bin, size_t len, unsigned char *dstPtr)
{
	if (dstPtr == NULL) {
		return false;
	}
	if (bin == NULL || len == 0) {
		return false;
	}

	for (int idx=0; idx<len; idx++) {
		*(dstPtr + idx*2) = "0123456789ABCDEF"[bin[idx] >> 4];
		*(dstPtr + idx*2+1) = "0123456789ABCDEF"[bin[idx] & 0x0F];
	}
    *(dstPtr + len*2) = '\0';

	return true;
}

int main(void) {
	unsigned char ahex = 0xFE;
	unsigned char astr[3];
	bool res;
	
	res = bin2hex((const unsigned char *)&ahex, 1, astr);
	if (res) {
		printf("%s\n", astr);
	}

	return 0;
}

Result

stdout

FE