Functions Questions and Answers

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.

Q: What is the return type of the function sqrt()?

Correct answer: doublesqrt is declared in <math.h> as double sqrt(double) - it takes and returns a double. C99 added sqrtf and sqrtl for float and long double, but the return type of sqrt itself does not vary with the argument.

Q: What is the output of this C code? void foo(); int main() { void foo(int); foo(1); return 0; } void foo(int i) { printf("2 "); }

Correct answer: 2The declaration inside main - void foo(int) - is the one in scope at the call, so foo(1) matches it, and it agrees with the definition. The outer void foo() declares a function with an unspecified parameter list rather than none, so it does not conflict. The program prints 2.

Q: What is the output of code given below? enum m{JAN, FEB, MAR}; enum m foo(); int main() { enum m i = foo(); printf("%d\n", i); } int foo() { return JAN; }

Correct answer: Compile time errorThe prototype declares enum m foo(); but the definition is written int foo(). The two conflict, and the compiler rejects the program - even though an enumeration is represented as an integer, the declared types must match.

Q: Which variable has the longest scope? int b; int main() { int c; return 0; } int a;

Correct answer: bScope runs from the point of declaration onwards, so b, declared at the very top, is visible through the whole file - the longest scope of the three. a is declared at the bottom and so is visible almost nowhere, and c is local to main.

41.

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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42.

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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43.

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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44.

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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45.

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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46.

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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47.

What is the return type of the function sqrt()?

A.int
B.float
C.double
D.Depends on the data type of the parameter

Answer: C

Correct answer: double

sqrt is declared in <math.h> as double sqrt(double) - it takes and returns a double. C99 added sqrtf and sqrtl for float and long double, but the return type of sqrt itself does not vary with the argument.

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48.

What is the output of this C code?

void foo();
int main()
{
void foo(int);
foo(1);
return 0;
}
void foo(int i)
{
printf("2 ");
}

A.2
B.Compile time error
C.Depends on the compiler
D.Depends on the standard

Answer: A

Correct answer: 2

The declaration inside main - void foo(int) - is the one in scope at the call, so foo(1) matches it, and it agrees with the definition. The outer void foo() declares a function with an unspecified parameter list rather than none, so it does not conflict. The program prints 2.

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49.

What is the output of code given below?

enum m{JAN, FEB, MAR};
    enum m foo();
    int main()
    {
        enum m i = foo();
        printf("%d\n", i);
    }
    int  foo()
    {
        return JAN;
    }

A.Compile time error
B.Depends on the compiler
C.Depends on the standard

Answer: A

Correct answer: Compile time error

The prototype declares enum m foo(); but the definition is written int foo(). The two conflict, and the compiler rejects the program - even though an enumeration is represented as an integer, the declared types must match.

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50.

Which variable has the longest scope?

int b;
    int main()
    {
        int c;
        return 0;
    }
    int a;

A.a
B.b
C.c
D.Both (a) and (b)

Answer: B

Correct answer: b

Scope runs from the point of declaration onwards, so b, declared at the very top, is visible through the whole file - the longest scope of the three. a is declared at the bottom and so is visible almost nowhere, and c is local to main.

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