C Programming – Variable Length Argument

C Programming - Variable Length Argument

Question 1

What is the output of this C code?

    #include 
    #include 
    void func(int, ...);
    int main()
    {
    func(2, 3, 5, 7, 11, 13);
    return 0;
    }
    void func(int n, ...)
    {
    int number, i = 0;
    va_list start;
    va_start(start, n);
    while (i != 3)
    {
    number = va_arg(start, int);
    i++;
    }
    printf("%d", number);
    }

A	3
B	5
C	7
D	11

Question 2

Which of the following function with ellipsis are illegal?

A	void func(…);
B	void func(int, …);
C	void func(int, int, …);
D	Both (a) and (c)

Question 3

Which of the following data-types are promoted when used as a parameter for an ellipsis?

A	char
B	short
C	int
D	None of the mentioned

Question 4

Which header file includes a function for variable number of arguments?

A	stdlib.h
B	stdarg.h
C	ctype.h
D	Both (a) and (b)

Question 5

Which of the following macro extracts an argument from the variable argument list (ie ellipsis) and advance the pointer to the next argument?

A	va_list
B	va_arg
C	va_end
D	va_start

Question 6

The type va_list is used in an argument list

A	To declare a variable that will refer to each argument in turn;
B	For cleanup
C	To create a list
D	There is no such type

Question 7

The declaration … can

A	Appear anywhere in the function declaration
B	Only appear at the end of an argument list.
C	Nothing
D	Both a & b

Question 8

Each call of va_arg

A	returns one argument
B	Steps va_list variable to the next
C	Both a & b
D	None of the mentioned

Question 9

The standard header _______ is used for variable list arguments (…) in C.

A
B
C
D

Question 10

va_end does whatever.

A	Cleanup is necessary
B	Bust be called before the program returns.
C	Both a &
D	None of the mentioned

Question 11

What is the output of this C code?

    #include 
    int f(char chr, ...);
    int main()
    {
    char c = 97;
    f(c);
    return 0;
    }
    int f(char c, ...)
    {
    printf("%c\n", c);
    }

A	Compile time error
B	Undefined behaviour
C	97
D	a

Question 12

What is the output of this C code?

    #include 
    #include 
    int f(...);
    int main()
    {
    char c = 97;
    f(c);
    return 0;
    }
    int f(...)
    {
    va_list li;
    char c = va_arg(li, char);
    printf("%c\n", c);
    }

A	Compile time error
B	Undefined behaviour
C	97
D	a

Question 13

What is the output of this C code?

    #include 
    #include 
    int f(char c, ...);
    int main()
    {
    char c = 97, d = 98;
    f(c, d);
    return 0;
    }
    int f(char c, ...)
    {
    va_list li;
    va_start(li, c);
    char d = va_arg(li, char);
    printf("%c\n", d);
    va_end(li);
    }

A	Compile time error
B	Undefined behaviour
C	a
D	b

Question 14

What is the output of this C code?

    #include 
    #include 
    int f(char c, ...);
    int main()
    {
    char c = 97, d = 98;
    f(c, d);
    return 0;
    }
    int f(char c, ...)
    {
    va_list li;
    va_start(li, c);
    char d = va_arg(li, int);
    printf("%c\n", d);
    va_end(li);
    }

A	Compile time error
B	Undefined behaviour
C	a
D	b

Question 15

What is the output of this C code?

    #include 
    #include 
    int f(int c, ...);
    int main()
    {
    int c = 97;
    float d = 98;
    f(c, d);
    return 0;
    }
    int f(int c, ...)
    {
    va_list li;
    va_start(li, c);
    float d = va_arg(li, float);
    printf("%f\n", d);
    va_end(li);
    }

A	Compile time error
B	Undefined behaviour
C	97.000000
D	98.000000

Check Your Answers:

1. C

2. A

3. A

4. B

5. B

6. A

7. B

8. D

9. D

10. C

11. A

12. A

13. B

14. D

15. B

Balaji Mote

C Programming – Variable Length Argument