C语言：十进制、十六进制数据互换

int DectoHex(int dec, unsigned char *hex, int length) 
{ 
	for(int i=length-1; i>=0; i--) 
	{ 
		hex[i] = (dec%256)&0xFF; 
		dec /= 256; 
	} 
	
	return 0; 
} 

unsigned long HextoDec(const unsigned char *hex, int length) 
{ 
	unsigned long rslt = 0; 
	
	for(int i=0; i<length; i++) 
	{ 
		rslt += (unsigned long)(hex[i])<<(8*(length-1-i)); 
	} 
	
	return rslt; 
} 

int sprintf(char *str, const char *format, ...)

sprintf(&data, "十进制12的十六进制是%X", 12);

sprintf(&data, "十六进制0X12的十进制是%d", 0X12);