#include <iostream>
#include <string>
//Illustration of unions and bit-fields for "decoding" floating point

union number    // union: all members occupy the same memory space.
                // Changing any one member changes all members!
{
    struct			//bit fields
    {
        unsigned sign : 1;      // look at three float fields
        unsigned expo: 8;
        unsigned mant: 23;
    } flt;

    float floater;		// view as float
    int integer;		// view as int
    unsigned unsign;		// view as unsigned int
};


void floatFields(number x)
{
    cout << "As a floating point number: sign=" << x.flt.sign <<
    " exponent=" << x.flt.expo << " mantissa=" << x.flt.mant << endl;
}


int strbin(string word)               
// pre: word is valid representation of a hex number using lower case
// post: returns equivalent integer
{
    int c, j, l;
    if (word == "")
        return 0;
    l = word.length();
    c = word[l-1];
    if ( '0' <= c && c <= '9')
        j =  c - '0';
    else
        j = c - 'a' + 10;
    if (l == 1)
        return j;
    else
        return 16 * strbin(word.substr(0,l-1)) + j;
}

int main()
{
    number x;            // number is a union
    string word;

    cout << "Number(hex): ";
    while (cin >> word)
    {
        x.unsign = strbin(word);
        cout << hex << x.unsign << dec << " " << x.integer << " "
           << x.unsign << " " << x.floater << endl;
        floatFields(x);
        cout << "Number(hex): ";
    }

    return 0;
}