#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <math.h>
#include <errno.h>
#include <fenv.h>

const int FloatExpLen = 8;
const int FloatMantissaLen = 23;
const int FloatBits = FloatExpLen + FloatMantissaLen + 1;

void print_float_in_binary (float a)
{
        uint32_t t;
        memcpy (&t, &a, sizeof(float));

        // sign
        printf ("%d ", (t>>(FloatBits-1))&1);

        // exponent
        for (int i=(FloatBits-2); i!=(FloatBits-2)-FloatExpLen; i--)
                printf ("%d", (t>>i)&1);
        printf (" ");

        // mantissa
        for (int i=(FloatBits-2)-FloatExpLen; i>=0; i--)
                printf ("%d", (t>>i)&1);
        printf (" 0x%08x", t);
};

int main()
{
        float a;
        //double a; // this will fix it
        int i;

        printf ("0.1: "); print_float_in_binary(0.1); printf ("\n");

        a = 0.0;
        printf ("a = 0.0;\n");
        printf ("%f %e ", a, a); print_float_in_binary(a); printf ("\n");
        feclearexcept(FE_ALL_EXCEPT);
        a += 0.1;
        if(fetestexcept(FE_INEXACT))
                printf ("FE_INEXACT\n");
        printf ("a += 0.1;\n");
        printf ("%f %e ", a, a); print_float_in_binary(a); printf ("\n");
        feclearexcept(FE_ALL_EXCEPT);
        a -= 0.1;

        if(fetestexcept(FE_INEXACT))
                printf ("FE_INEXACT\n");
        printf ("a -= 0.1;\n");
        printf ("%f %e ", a, a); print_float_in_binary(a); printf ("\n");

        if (a==0.0)
                printf ("a==0\n");
        else
                printf ("a!=0\n");

        for (i = 0; a < 1.0; i++) 
        {
                printf ("i=%d ", i);
                printf ("%f %e ", a, a); print_float_in_binary(a); printf ("\n");
                a += a;
        };

        printf("i=%d, a=%f %e\n", i, a, a);

        return 0;
}