IEEE-754标准（32位）十六进制与十进制浮点数之间的相互转换

IEEE-754标准（32位）十六进制转十进制浮点数

#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;}

十进制浮点数 转IEEE-754标准（32位）十六进制

#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1while (!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=0b = 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 1ite++;}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;}