C Bit-fields Quiz Online Practice Test

1. Which data types are valid for declaring bit-fields?

2. Which option helps in minimizing the size of a structure?

3. For what minimum value of x in a 32-bit Linux OS would the size of struct 's' be 8 bytes?

4. What percentage of memory is saved by using bit-fields in the following C structure compared to not using bit-fields? (Assume int size = 4)
struct temp
{
int a : 1;
int b : 2;
int c : 4;
int d : 4;
}s;

5. In the following bit-field declaration, the constant-expression specifies __________
struct-declarator:
declarator
type-specifier declarator opt : constant-expression

6. In the following bit-field declaration, the constant-expression must be __________
struct-declarator:
declarator
type-specifier declarator opt : constant-expression

7. Which of the following is not permitted?

8. Bit fields are restricted to being declared within a structure.

9. What is the validity of the following C bit-field declarations?
short a : 17;
int long y : 33;

10. What will be the result of executing the following C code?
#include <stdio.h>
struct p
{
char x : 2;
int y : 2;
};
int main()
{
struct p p;
p.x = 2;
p.y = 1;
p.x = p.x & p.y;
printf("%d\n", p.x);
}

11. What will be the output of this C code?
#include <stdio.h>
union u
{
struct p
{
unsigned char x : 2;
unsigned int y : 2;
};
int x;
};
int main()
{
union u u;
u.p.x = 2;
printf("%d\n", u.p.x);
}

12. What is the output of the following C code?
#include <stdio.h>
union u
{
struct
{
unsigned char x : 2;
unsigned int y : 2;
} p;
int x;
};
int main()
{
union u u;
u.p.x = 2;
printf("%d\n", u.p.x);
}

13. What will be the output when the following C code is executed?
#include <stdio.h>
union u
{
struct
{
unsigned char x : 2;
unsigned int y : 2;
} p;
int x;
};
int main()
{
union u u;
u.p.x = 2;
printf("%d\n", u.p.x);
}

14. What will the following C code output?
#include <stdio.h>
union u
{
struct
{
unsigned char x : 2;
unsigned int y : 2;
} p;
int x;
};
int main()
{
union u u = {2};
printf("%d\n", u.p.x);
}

15. What will be the output of this C code snippet?
#include <stdio.h>
union u
{
struct
{
unsigned char x : 2;
unsigned int y : 2;
} p;
int x;
};
int main()
{
union u u.p = {2};
printf("%d\n", u.p.x);
}

16. What will be the output of this C code?
#include <stdio.h>
struct p
{
unsigned int x : 2;
unsigned int y : 2;
};
int main()
{
struct p p;
p.x = 3;
p.y = 1;
printf("%d\n", sizeof(p));
}

17. What will be the output when this C code is executed?
#include <stdio.h>
struct p
{
unsigned int x : 2;
unsigned int y : 2;
};
int main()
{
struct p p;
p.x = 3;
p.y = 4;
printf("%d\n", p.y);
}

18. What will the following C code output when executed?
#include <stdio.h>
struct p
{
unsigned int x : 7;
unsigned int y : 2;
};
int main()
{
struct p p;
p.x = 110;
p.y = 2;
printf("%d\n", p.x);
}

19. What will be the output of the following C code when executed?
#include <stdio.h>
struct p
{
unsigned int x : 1;
unsigned int y : 1;
};
int main()
{
struct p p;
p.x = 1;
p.y = 2;
printf("%d\n", p.y);
}