Read/Write hex from/to a file in C?

Hello

I've googled this but I'm not getting much joy.

Does anyone know of an easy way to read/write hex from/to a file in C?

Thank you.

fscanf(f, "%x", &var); maybe

Thank you for your reply.

So if I have a text file called plaintext.txt with the following HEX:

0123456789ABCDEF

Should the following code work?

Code:

FILE *fp;
unsigned char message[8];

fp=fopen("c:\\plaintext.txt", "r");
fscanf(fp, "%x", &message);
fclose(fp);

Thank you

Should the following code work?

no...
read the scanf format description
read about %x format
read about maximum integer value
try to figure out your problems...

Here is the code, like yours, but it compiles:

Code:

#include <stdio.h>

int main(void)
{
	FILE *fp;
	unsigned int message;

	fp=fopen("c:\\plaintext.txt", "r");
	fscanf(fp, "%x", &message);
	printf("%x ", message);
	
	fclose(fp);
	
	return 0;
}

Here is the output:

Code:

89abcdef

Go from there. Looks to me like it's only printing the last 8 digits.