Functions Questions and Answers

Q: Which of the following is true of a static variable?

Correct answer: All of the mentionedAll three are true of a static local variable. It keeps its value between calls, because it is initialised once and its storage lasts as long as the program; it therefore still exists after the function returns; and although its name is local, its address can be passed to another function, which may then modify it through the pointer.

Q: What is the notation for the following functions? 1. int f(int a, float b) { /* Some code */ } 2. int f(a, b) int a; float b; { /* Some code */ }

Correct answer: 1. ANSI Notation 2. KR NotationThe first form declares each parameter’s type inside the parentheses - the ANSI (prototype) style, introduced by the 1989 standard. The second lists only the names in the parentheses and declares their types between the parentheses and the body - the old Kernighan and Ritchie style. The ANSI form matters because it lets the compiler check the arguments at every call; the K&R form does not, and is now obsolete.

Q: Can a function return an enumeration constant in C?

Correct answer: trueAn enumeration constant is an integer constant, so a function can return one exactly as it returns any int - and a function may equally be declared to return the enumeration type itself.

Q: What is the output of this code having void return-type function? void foo() { return 1; } void main() { int x = 0; x = foo(); printf("%d", x); }

Correct answer: Compile time errorA void function must not return a value, so return 1; is an error - and assigning the result of a void function to an int is a second one. Either alone would stop the program compiling.

Q: The output of the code below is int *m(); void main() { int k = m(); printf("%d", k); } int *m() { int a[2] = {5, 8}; return a; }

Correct answer: VariesTwo faults compound each other. The function returns a pointer to a local array that no longer exists, and the caller assigns that pointer to an int. What is printed is an address reinterpreted as an integer - different on every run and every machine.

Q: Maximum number of arguments that a function can take is 12

Correct answer: NoThe standard sets no limit of twelve. It requires an implementation to support at least 127 parameters, and most allow far more - so the practical limit is the compiler’s, not the language’s. (A function needing many parameters is usually better given a structure.)

Q: What is the output of this C code? static int x; void main() { int x; printf("x is %d", x); }

Correct answer: Junk valueThe local int x; shadows the file-scope static, and being an automatic variable with no initialiser it holds whatever was on the stack - a junk value. Only variables with static storage duration are zeroed for you.

Q: Functions cannot return more than one value at a time

Correct answer: TrueA C function returns at most one value. Where more is needed the usual devices are to pass pointers for the extra results, or to return a structure containing them all.

Q: What linkage does automatic variables have?

Correct answer: No linkageAn automatic variable has no linkage: its name refers to a fresh object on each entry to the block and cannot be referred to from anywhere else - not from another file, not even from another function. Only file-scope names have linkage, internal or external.

Q: What is the output of this C code? void main() { int x = 3; { x = 4; printf("%d", x); } }

Correct answer: 4The inner block contains an assignment, not a declaration, so it changes the x already in scope. The value printed is 4.

41.

Which of the following is true of a static variable?

A.It retains its value between calls to the function.
B.It exists even after the function ends.
C.It can be modified in another function by sending it as a parameter.
D.All of the mentioned

Answer: C

Correct answer: All of the mentioned

All three are true of a static local variable. It keeps its value between calls, because it is initialised once and its storage lasts as long as the program; it therefore still exists after the function returns; and although its name is local, its address can be passed to another function, which may then modify it through the pointer.

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42.

What is the notation for the following functions?

1.  int f(int a, float b)
    {
        /* Some code */
    }

2.  int f(a, b)
    int a; float b;
    {
        /* Some code */
    }

A.1. KR Notation 2. ANSI Notation
B.1. Pre ANSI C Notation 2. KR Notation
C.1. ANSI Notation 2. KR Notation
D.1. ANSI Notation 2. Pre ANSI Notation

Answer: C

Correct answer: 1. ANSI Notation 2. KR Notation

The first form declares each parameter’s type inside the parentheses - the ANSI (prototype) style, introduced by the 1989 standard. The second lists only the names in the parentheses and declares their types between the parentheses and the body - the old Kernighan and Ritchie style. The ANSI form matters because it lets the compiler check the arguments at every call; the K&R form does not, and is now obsolete.

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43.

Can a function return an enumeration constant in C?

A.true
B.false
C.depends on the compiler
D.depends on the standard

Answer: A

Correct answer: true

An enumeration constant is an integer constant, so a function can return one exactly as it returns any int - and a function may equally be declared to return the enumeration type itself.

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44.

What is the output of this code having void return-type function?

void foo()
    {
        return 1;
    }

    void main()
    {
        int x = 0;
        x = foo();
        printf("%d", x);
     }

A.1
B.Runtime error
C.Compile time error

Answer: C

Correct answer: Compile time error

A void function must not return a value, so return 1; is an error - and assigning the result of a void function to an int is a second one. Either alone would stop the program compiling.

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45.

The output of the code below is

int *m();
    void main()
    {
        int k = m();
        printf("%d", k);
    }
    int *m()
    {
        int a[2] = {5, 8};
        return a;
    }

A.5
B.8
C.Nothing
D.Varies

Answer: D

Correct answer: Varies

Two faults compound each other. The function returns a pointer to a local array that no longer exists, and the caller assigns that pointer to an int. What is printed is an address reinterpreted as an integer - different on every run and every machine.

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46.

Maximum number of arguments that a function can take is 12

A.Yes
B.No

Answer: B

Correct answer: No

The standard sets no limit of twelve. It requires an implementation to support at least 127 parameters, and most allow far more - so the practical limit is the compiler’s, not the language’s. (A function needing many parameters is usually better given a structure.)

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47.

What is the output of this C code?

static int x;
    void main()
    {
        int x;
        printf("x is %d", x);
    }

A.Junk value
B.Run time error
C.Nothing

Answer: A

Correct answer: Junk value

The local int x; shadows the file-scope static, and being an automatic variable with no initialiser it holds whatever was on the stack - a junk value. Only variables with static storage duration are zeroed for you.

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48.

Functions cannot return more than one value at a time

A.True
B.False

Answer: A

Correct answer: True

A C function returns at most one value. Where more is needed the usual devices are to pass pointers for the extra results, or to return a structure containing them all.

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49.

What linkage does automatic variables have?

A.Internal linkage
B.External linkage
C.No linkage
D.None of the mentioned

Answer: C

Correct answer: No linkage

An automatic variable has no linkage: its name refers to a fresh object on each entry to the block and cannot be referred to from anywhere else - not from another file, not even from another function. Only file-scope names have linkage, internal or external.

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50.

What is the output of this C code?

void main()
    {
        int x = 3;
        {
            x = 4;
            printf("%d", x);
        }
    }

A.4
B.3
C.Undefined

Answer: A

Correct answer: 4

The inner block contains an assignment, not a declaration, so it changes the x already in scope. The value printed is 4.

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