To create a variable that takes only 3 bits memory

CODE:
#include<stdio.h>
#include<conio.h>
struct abc

{

   unsigned xyz : 3; //takes 3 bit memory

}st;

void main()

{
   clrscr();
   st.xyz = 7; //(1112) 
   printf("\nValue of xyz(before increment) : %d",st.xyz);
   st.xyz++;
   printf("\nValue of xyz(after increment) : %d",st.xyz);
   getch();
}


OUTPUT:
Value of xyz(before increment) : 7
Value of xyz(after increment) : 0