BitField sheningans.

#include <iostream>
#include <cstdlib>
#include <bitset>

union flt      {
   struct ieee754  {
      unsigned short mantissa:23; // 23 > sizeof(short)
      unsigned short exponent:8;
      unsigned short     sign:1;
    }   raw   ;  //  23 + 8 + 1 = 32 bits =  4 byte
   unsigned int f;
};

int main()
{
    flt a;
    a.f = 0x84229FFF;
    std::cout << "a.f =\t\t " << std::bitset<32>(a.f) << std::endl;
    std::cout << "a.mantissa =\t\t  " <<std::bitset<23>(a.raw.mantissa) << std::endl;
    std::cout << "a.exponent =\t  " <<std::bitset<8>(a.raw.exponent) << std::endl;
    std::cout << "a.sign =\t " << std::bitset<1>(a.raw.sign) << std::endl;


}

/*
Output
a.f =          10000100001000101001111111111111
a.mantissa =            00000001001111111111111
a.exponent =    00001000
a.sign =       1
*/