c++中如何实现二进制（Bin）与 十六进制（Hex）之间的相互转换

1. 二进制 -> 十六进制

#include "stdafx.h"
#include "iostream"
#include "string"

using namespace std;

//二进制 -》十六进制
string BinStrToHexStr(string str)
{
	string str_Hex = "";
	string temp_Hex = "";
	int iHex = 0;
	if (str.size() % 4 != 0)
	{
		int num = 4 - (str.size() % 4);
		for (int i = 0; i < num; i++)
		{
			str = "0" + str;
		}
	}
	for (int i = 0; i < str.size(); i += 4)
	{
		iHex = (str[i] - '0') * 8 + (str[i + 1] - '0') * 4 + (str[i + 2] - '0') * 2 + (str[i + 3] - '0') * 1;
		if (iHex >= 10)
		{
			int left = iHex % 16;
			temp_Hex = 'A' + left - 10;
		}
		else
		{
			temp_Hex = to_string(iHex);
		}
		str_Hex += temp_Hex;
	}
	return str_Hex;
}

int main()
{
	string str_2 = "1111011";
	cout << "二进制:" << str_2.c_str() << endl;
	string str_Hex = BinStrToHexStr(str_2);
	cout << "十六进制：0x" << str_Hex.c_str() << endl;
	system("pause");
}

结果验证：

2. 十六进制 -> 二进制

#include "stdafx.h"
#include "iostream"
#include "string"
#include "vector"
#include 

using namespace std;

#define TOLOWER(p) {transform(p.begin(),p.end(),p.begin(),::tolower);}

//十六进制 -> 二进制
string HexStrToBinStr(string str)
{
	string str_Bin = "";
	int iDec = 0;
	TOLOWER(str);
	sscanf_s(str.c_str(), "%x", &iDec);
	vector<int>vec_remder;
	int remder = 0;
	while (iDec / 2 != 0)
	{
		remder = iDec % 2;
		vec_remder.push_back(remder);
		iDec /= 2;
	}
	remder = iDec % 2;
	vec_remder.push_back(remder);
	reverse(vec_remder.begin(), vec_remder.end());
	for (int i = 0; i < vec_remder.size(); i++)
	{
		str_Bin += to_string(vec_remder[i]);
	}
	return str_Bin;
}


int main()
{
	string str_16 = "7B";
	cout << "十六进制：0x" << str_16.c_str() << endl;
	string str_Bin = HexStrToBinStr(str_16);
	cout << "二进制:" << str_Bin.c_str() << endl;
	system("pause");
}

结果验证：