union in struct with bit fields

hi ,
I am having bit field packed in union of struct..
but not able to retrieve values correctly
/..........

My code is
My code is
insert

Code:

---

#include <string.h>
#include <stdio.h>

typedef union
        {
        unsigned dd:4;
        unsigned ee;

        }ff;

typedef struct {
        int unittype:2;
        ff ss;
        union {
        int units:3;
        } howmuch ;
        //amount howmuch;
        } product;
int main()
{

        product dieselmotorbike;

        product * myebaystore[2];
        int nitems = 1; int i;

        dieselmotorbike.unittype = 1;

        dieselmotorbike.howmuch.units = 3;

        dieselmotorbike.ss.dd = 14;
        dieselmotorbike.ss.ee = 4;


        myebaystore[0] = &dieselmotorbike;

        for (i=0; i<nitems; i++) {
                switch (myebaystore[i]->unittype) {
                case 1:
                                printf("We have &#37;u units for sale kg \n %u      ",
                                myebaystore[i]->howmuch.units,
                                myebaystore[i]->ss.dd,
                                myebaystore[i]->ss.ee);

                        break;
                case 2:
                        printf("We have %f kgs for sale\n",
                                myebaystore[i]->howmuch.units);
                        break;
                }
        }
}

[code

---

If i print the values they print last updated element ...........
Please suggest the remedy..........


Sagar...

Not sure what you expect, but certainly this:

Code:

---

typedef union
        {
        unsigned dd:4;
        unsigned ee;

        }ff;

---

is one field, which you can either use as a 4-bit field or a (presumably) 32-bit. ee and dd will cover the same piece of memory (but of course dd is bigger, so it will cover some memory that is not covered by dd).

--
Mats

in the program if i assigned value to my dd and ee separetely they should print their own values but still they are giving last eneterd value..

What do you mean by
" ee and dd will cover the same piece of memory (but of course dd is bigger, so it will cover some memory that is not covered by dd). "

Quote:

---

Originally Posted by sagarnewase

in the program if i assigned value to my dd and ee separetely they should print their own values but still they are giving last eneterd value..

---

My turn to ask what you mean?

Quote:

---

What do you mean by
" ee and dd will cover the same piece of memory (but of course dd is bigger, so it will cover some memory that is not covered by dd). "

---

I mean that ee and dd overlap each other in the same location of memory.

Consider this:

Code:

---

union a
{
    int x;
    int y;
};

---

Now, x and y will have exactly the same memory address, and if we write this:

Code:

---

union a aa;

...
aa.x = 7;
aa.y = 8;
printf("aa.x = %d\n", aa.x);

---

This will produce 8 as the output.

--
Mats