Mutual conversion between IEEE-754 standard (32-bit) hexadecimal and decimal floating-point numbers

IEEE-754 standard (32-bit) hexadecimal to decimal floating point number

#include<fstream>
#include <sstream>
#include <iostream>
#include<math.h>
using namespace std;

double BtoD(string x)
{
    
    
    double ans;
    int E = 0;
    double D = 0;
    for (int i = 1; i < 32; i++)
    {
    
    
        if (i < 9)
        {
    
    
            E += (x[i] - '0') << (8 - i);
            //cout << E << endl;
        }
        else
        {
    
    
            D += (x[i] - '0') * pow(2 ,(8 - i));
            //cout << D << endl;
        }

    }

    ans = pow(2, E - 127)*(1+D);

    if (x[0] = '1')
        ans = -ans;

    return -ans;
}



int main()
{
    
    

    string input;
    ifstream in;
    in.open("D:\\p1.txt");


    if (!in.good())
    {
    
    
        cout << "文件打开失败" << endl;
        system("pause");
        return 0;
    }
    while (!in.eof())
    {
    
    

        in >> input;
        cout << input << endl;;
        cout << BtoD(input) << endl;

        system("pause");
    }



    in.close();
    cout << "转换完成" << endl;
    system("pause");

    return 0;

}

Convert decimal floating point number to IEEE-754 standard (32-bit) hexadecimal

#include<iostream>
#include<vector>
#include"math.h"
#include<iomanip>
#include <fstream>

using namespace std;

vector<bool> zhengshu;//存整数部分的二进制
vector<bool> xiaoshu;//存小数部分的二进制

vector<bool> get_zhengshu_2b(float a)
{
    
    
	vector<bool> x;
	x.clear();
	//八位二进制a xxxx xxxx与1000 0000与，得到每位的二进制数
	for (int i = 0; i < 8; i++)
	{
    
    
		if ((((int)a)&(0x80 >> i)))
		{
    
    
			x.push_back(1);
		}
		else
		{
    
    
			x.push_back(0);
		}
	}
	return x;
}

void get_2b(float a)
{
    
    
	//获取整数部分的二进制码
	float fabs_a = fabs(a);//取绝对值
	zhengshu.clear();
	xiaoshu.clear();
	zhengshu = get_zhengshu_2b(fabs_a);

	//获取小数部分的二进制码
	float n = 2;   //小数位的阶数取倒数
	float b = (fabs_a - floor(fabs_a));

	//每次除以2判断该位是0还是1
	while (!b == 0)
	{
    
    
		if ((1.0 / n) < b)
		{
    
    
			xiaoshu.push_back(1);
			//若为1则b减去该位所对应的十进制小数大小 ，继续判断低一位，直到b=0
			b = b - (1.0 / n);
		}
		else if ((1.0 / n) > b)
		{
    
    
			xiaoshu.push_back(0);
		}
		else if ((1.0 / n) == b)
		{
    
    
			xiaoshu.push_back(1);
			break;
		}
		n = n * 2;
	}
}
int get_jiema()  //返回阶码
{
    
    
	for (int i = 0; i < 8; i++)
	{
    
    
		if (zhengshu[i] == 1)//判断从左边起第一个为1的位置
			return 7 - i;		// 返回阶码大小
	}
}
vector<bool> get_yima()//得到移码
{
    
    
	int e = get_jiema();
	e = e + 127;  //阶码偏移得到移码
	return get_zhengshu_2b(e);//返回获得的移码的二进制形式
}
vector<bool> get_weima()//获得尾码
{
    
    
	vector <bool> m;
	//小数的二进制前插入规格化的码得到尾码
	xiaoshu.insert(xiaoshu.begin(), zhengshu.begin() + (8 - get_jiema()), zhengshu.end());
	m = xiaoshu;
	return m;
}
vector<bool> to_IEEE754(float x)
{
    
    
	vector<bool> IEEE;
	IEEE.clear();
	get_2b(x);   //得到x的二进制码
	/*
	//输出原数的二进制形式
	cout << "绝对值的二进制数为：" << endl;
	for (int i = 0; i < zhengshu.size(); i++)
	{
		cout << zhengshu[i];
	}
	cout << ".";
	for (int i = 0; i < xiaoshu.size(); i++)
	{
		cout << xiaoshu[i];
	}
	cout << endl;
	//输出移码
	cout << "移码为：" << endl;


	vector<bool> E = get_yima();
	for (int i = 0; i < 8; i++)
	{
		cout << E[i];
	}
	cout << endl;
	*/
	//组合成短浮点数代码：
	vector<bool> yima;
	yima.clear();
	yima = get_yima();
	vector<bool> weima;
	weima.clear();
	weima = get_weima();

	if (x > 0)//判断并添加符号位
	{
    
    
		IEEE.insert(IEEE.end(), 1, 0);
	}
	else
	{
    
    
		IEEE.insert(IEEE.end(), 1, 1);
	}
	IEEE.insert(IEEE.end(), yima.begin(), yima.end());//添加移码
	IEEE.insert(IEEE.end(), weima.begin(), weima.end());//添加尾码
	IEEE.insert(IEEE.end(), 32 - 9 - weima.size(), 0);//尾部补零 共32位
	return IEEE;
}
void get_hex(vector<bool> E)//得到十六进制显示
{
    
    
	ofstream out;
	out.open("D:\\Desktop\\输出.txt", ios::app);

	vector<bool>::iterator ite = E.begin();//迭代器
	int sum = 0;
	int n = 8;
	while (n--)//八组循环
	{
    
    
		for (int i = 0; i < 4; i++)//求每4位的十六进制表示
		{
    
    
			sum = sum + (*ite)*pow(2, 3 - i);//8 4 2 1
			ite++;
		}

		cout << setiosflags(ios::uppercase) << hex << sum;//16进制大写字母输出

		out << setiosflags(ios::uppercase) << hex << sum;// 写入文件
		sum = 0;
	}
	out << endl;
	out.close();
	cout << endl;
}



int main()
{
    
    

	ifstream in;
	in.open("D:\\P1.txt");
	//求十进制的短浮点数代码//

	if (!in.good())
	{
    
    
		cout << "文件打开失败" << endl;
		system("pause");
		return 0;
	}
	while (!in.eof())
	{
    
    
		float x;
		vector<bool> IEEE;
		in >> x;
		cout << x <<"转换为：" ;
		IEEE = to_IEEE754(x);
		get_hex(IEEE);
		IEEE.clear();
		cout  << endl;
		//system("pause");
	}
	in.close();
	cout << "转换完成" << endl;
	system("pause");

	return 0;

}