C++如何实现BCD码和ASCII码的相互转换

#include<iostream>
#include<stdlib.h>
#include<string>
using namespace std;

string ASCII2BCD(const string &str)
{
	string	res;
	size_t	nBegin = 0;
	int	nTemp;
	char	szBuf[16] = { 0 };
	if (str.size() % 2 != 0)
	{
		szBuf[0] = '0';
		szBuf[1] = str[0];
		sscanf(szBuf, "%x", &nTemp);
		nBegin = 1;
		res.push_back((char)nTemp);
	}
	for (; nBegin < str.size(); nBegin += 2)
	{
		szBuf[0] = str[nBegin];
		szBuf[1] = str[nBegin + 1];
		sscanf(szBuf, "%x", &nTemp);
		res.push_back((char)nTemp);
	}
	return res;
}

string	BCD2ASCII(const string &str)
{
	string res;
	for (size_t i = 0; i < str.size(); i++)
	{
		char temp = (str[i] >> 4) & 0x0F;
		if (temp >= 10)
			res.push_back('A' + temp - 10);
		else
			res.push_back('0' + temp);
		temp = str[i] & 0x0F;
		if (temp >= 10)
			res.push_back('A' + temp - 10);
		else
			res.push_back('0' + temp);
	}
	return res;
}

int main()
{
	string str1 = BCD2ASCII("王通"); //BCD转ASCII
	for (int i = 0; i < str1.length(); i++)
	{
		cout << str1[i];
	}
	cout << endl;

	string str2 = ASCII2BCD(str1); //ASCII转BCD

	for (int i = 0; i < str2.length(); i++)
	{
		cout << str2[i];
	}
	cout << endl;
	return 0;
}