Decimal, 16 binary, BCD Mutual

Output:
//
Returns: int rslt converted decimal data
//
Train of thought: hexadecimal the range of decimal digits represented by each character bit is 0 ~255, and the system is 256.
Left 8-bit (<<8) equivalent multiplied by 256
//
/////////////////////////////////////////////////////////
unsigned long hextodec (const unsigned char *hex, int length)
{
int i;
unsigned long rslt = 0;
for (i=0; i<length; i++)
{
Rslt + = (unsigned long) (Hex[i]) << (8* (length-1-i));

}
return rslt;
}
/////////////////////////////////////////////////////////
//
function: decimal hexadecimal
//
Input: int Dec decimal data for conversion
Length of the hexadecimal data after the int length conversion
//
Output: Hexadecimal data converted by unsigned char *hex
//
Return: 0 Success
//
Train of thought: Principle with hexadecimal turn decimal
//////////////////////////////////////////////////////////
int dectohex (int dec, unsigned char *hex, int length)
{
int i;
for (i=length-1; i>=0; i--)
{
Hex[i] = (dec%256) &0xFF;
Dec/= 256;
}
return 0;
}
/////////////////////////////////////////////////////////
//
Function: the right to ask
//
Input: int base into base
Int times Right Series
//
Output:
//
Return: unsigned long the current data bit right
//
//////////////////////////////////////////////////////////
unsigned long (int base, int times)
{
int i;
unsigned long rslt = 1;
for (i=0; i<times; i++)
Rslt *= Base;
return rslt;
}
/////////////////////////////////////////////////////////
//
Function: BCD 10 system
//
Input: const unsigned char *BCD BCD code to convert
int length BCD code data lengths
//
Output:
//
Return: unsigned long the current data bit right
//
Idea: Compress BCD Code a character represents a decimal data range of 0 ~ 99, the system is 100
First ask for the decimal value represented by each character, then multiply the right
//////////////////////////////////////////////////////////
unsigned long bcdtodec (const unsigned char *bcd, int length)
{
int I, TMP;
unsigned long dec = 0;
for (i=0; i<length; i++)
{
TMP = ((bcd[i]>>4) &0x0f) *10 + (bcd[i]&0x0f);
Dec + = tmp * Power (MB, length-1-i);
}
return Dec;
}
/////////////////////////////////////////////////////////
//
Function: Decimal Conversion BCD Code
//
Input: int DEC decimal data for conversion
int length BCD code data lengths
//
Output: unsigned char *BCD converted BCD Code
//
Return: 0 Success
//
Train of thought: Principle with BCD code turn decimal
//
//////////////////////////////////////////////////////////
int DECTOBCD (int Dec, unsigned char *bcd, int length)
{
int i;
int temp;
for (i=length-1; i>=0; i--)
{
         temp = dec%100;