C Programming Questions and Answers - Variable Length Argument - Syncsort, Synopsys

This section on C programming questions and answers focuses on “Variable Length Argument”. One shall practice these questions to improve their C programming skills needed for various interviews (campus interviews, walkin interviews, company interviews), placements, entrance exams and other competitive exams. These questions can be attempted by anyone focusing on learning C Programming language. They can be a beginner, fresher, engineering graduate or an experienced IT professional. Our C programming questions come with detailed explanation of the answers which helps in better understanding of C concepts.

Here is a listing of C programming questions on “Variable Length Argument” along with answers, explanations and/or solutions:

1. What is the output of this C code?

```
    #include <stdio.h>
```
```
    #include <stdarg.h>
```
```
    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
View Answer

Answer: c
Explanation: None.

2. Which of the following function with ellipsis are illegal?
a) void func(…);
b) void func(int, …);
c) void func(int, int, …);
d) none of the mentioned
View Answer

Answer: a
Explanation: None.

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
View Answer

Answer: a
Explanation: None.

4. Which header file includes a function for variable number of arguments?
a) stdlib.h
b) stdarg.h
c) ctype.h
d) both stdlib.h and stdarg.h
View Answer

Answer: b
Explanation: None.

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
View Answer

Answer: b
Explanation: None.

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
View Answer

Answer: a
Explanation: None.

7. The declaration … can
a) Appear anywhere in the function declaration
b) Only appear at the end of an argument list
c) Nothing
d) None of the mentioned
View Answer

Answer: b
Explanation: None.

8. Each call of va_arg
a) Returns one argument
b) Steps va_list variable to the next
c) Returns one argument & Steps va_list variable to the next
d) None of the mentioned
View Answer

Answer: c
Explanation: None.

Sanfoundry Global Education & Learning Series – C Programming Language.

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