hex2float.cpp

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

union fi{
    uint32_t i;
    float f;
} ;

uint32_t hex2int(string hex) {
    // std::stoiがうまく機能しないので自分で実装。
    int ofst = (hex.at(1) == 'x') ? 2 : 0;
    uint32_t ret = 0x00000000;
    for (int i=0; i<hex.size()-ofst; i++){
        ret <<= 4;
        if ((uint32_t)(hex.at(i + ofst) - '0') < 10){ // num
            ret += (uint32_t)(hex.at(i + ofst) - '0');
        } 
        else {
            ret += (uint32_t)(hex.at(i + ofst) - 'A') + (uint32_t)10;
        }
    }
    return ret;
}



int main (int argc, char** argv){
    if (argv[1][0] == 'd'){
        while (1) {
            uint32_t s;
            cin >> s;
            union fi fl;
            fl.i = s;
            printf("%8.8f\n", fl.f);
            cout << hex << "0x" << fl.i << endl;
        }
    }
    else if (argv[1][0] == 'b'){
        union fi temp;
        string str;
        while (1){
            cin >> str;
            temp.i = stoul(str, 0, 2);
            cout << temp.f << endl;
        }
    }
    else {
        // 16進
        while (1) {
            string s;
            cin >> s;
            uint32_t float_bit = hex2int(s);
            union fi fl;
            fl.i = float_bit;
            cout << hex << float_bit << endl;
            printf("%8.8f\n", fl.f);
        }
    }
    return 0;
}