Functions Questions and Answers

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.

Q: What is the output of this C code? int *i; int main() { if (i == NULL) printf("true\n"); return 0; }

Correct answer: truei is at file scope with no initialiser, so it is zero-initialised - and for a pointer that means the null pointer. The comparison with NULL therefore succeeds and true is printed.

Q: What is the output of the following program? #include <stdio.h> void swap(int m, int n) { int x = m; m = n; n = x; } main() { int x=5, y=3; swap(x,y); printf("%d %d", x, y); }

Correct answer: 5 3C passes arguments by value, so swap receives copies and exchanges the copies. The originals in main are untouched, and the output is 5 3. To swap the caller’s variables the function must take pointers and be called as swap(&x, &y).

Q: The variable declaration with no storage class specified is by default:

Correct answer: autoWith no storage class specified, a variable declared inside a block is auto. (At file scope the default is different: external linkage and static storage duration.)

Q: Can a function return a structure in C?

Correct answer: trueA function may return a structure, and the whole structure is copied back to the caller. It is the standard way of returning several values at once - and it is why the language does not need multiple return values. Returning a large structure copies a good deal of data, so a pointer is often preferred for big ones.

Q: What is the output of this C code? int x = 5; void main() { int x = 3; printf("%d", x); { x = 4; } printf("%d", x); }

Correct answer: 3 4The inner x = 4; is an assignment, not a declaration, so it changes the x already in scope - main's local. The first printf shows 3 and the second, after the block, shows 4. The file-scope x = 5 is shadowed throughout and never seen.

51.

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.

Discuss in Forum

52.

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.

Discuss in Forum

53.

What is the scope of an external variable?

A.Whole source file in which it is defined
B.From the point of declaration to the end of the file in which it is defined
C.Any source file in a program
D.From the point of declaration to the end of the file being compiled

Answer: D

Correct answer: From the point of declaration to the end of the file being compiled

Scope runs from the point of declaration to the end of the file - a variable declared at the bottom of a file is not visible to functions above it. Being reachable from other files is a matter of linkage, which is a different property; an extern declaration in the other file is what brings it into scope there.

Discuss in Forum

54.

What is the scope of a function?

A.Whole source file in which it is defined
B.From the point of declaration to the end of the file in which it is defined
C.Any source file in a program
D.From the point of declaration to the end of the file being compiled

Answer: D

Correct answer: From the point of declaration to the end of the file being compiled

A function’s name is in scope from its declaration to the end of the file - which is exactly why prototypes are put at the top or in a header. Its linkage is external, so other files can call it once they have declared it.

Discuss in Forum

55.

What is the output of this C code?

int *i;
    int main()
    {
        if (i == NULL)
            printf("true\n");
        return 0;
    }

A.true
B.true only if NULL value is 0
C.Compile time error
D.Nothing

Answer: A

Correct answer: true

i is at file scope with no initialiser, so it is zero-initialised - and for a pointer that means the null pointer. The comparison with NULL therefore succeeds and true is printed.

Discuss in Forum

56.

What is the output of the following program?

#include <stdio.h>

void swap(int m, int n)
{
   int x = m;
   
   m = n;
   n = x;
}
main()
{
   int x=5, y=3;

   swap(x,y);
   printf("%d %d", x, y);
}

A.3 5
B.5 3
C.5 5
D.Compile error

Answer: B

Correct answer: 5 3

C passes arguments by value, so swap receives copies and exchanges the copies. The originals in main are untouched, and the output is 5 3. To swap the caller’s variables the function must take pointers and be called as swap(&x, &y).

Discuss in Forum

57.

The variable declaration with no storage class specified is by default:

A.auto
B.extern
C.static
D.register

Answer: A

Correct answer: auto

With no storage class specified, a variable declared inside a block is auto. (At file scope the default is different: external linkage and static storage duration.)

Discuss in Forum

58.

Can a function return a structure in C?

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

Answer: A

Correct answer: true

A function may return a structure, and the whole structure is copied back to the caller. It is the standard way of returning several values at once - and it is why the language does not need multiple return values. Returning a large structure copies a good deal of data, so a pointer is often preferred for big ones.

Discuss in Forum

59.

Is it true that too many recursive calls may result into stack overflow?

A.Yes
B.No

Answer: A

Yes, too many recursive calls may result into stack overflow. because when a function is called its return address is stored in stack.

After sometime the stack memory will be filled completely. Hence stack overflow error will occur.

Discuss in Forum

60.

What is the output of this C code?

int x = 5;
    void main()
    {
        int x = 3;
        printf("%d", x);
        {
            x = 4;
        }
        printf("%d", x);
    }

A.Run time error
B.3 3
C.3 5
D.3 4

Answer: D

Correct answer: 3 4

The inner x = 4; is an assignment, not a declaration, so it changes the x already in scope - main's local. The first printf shows 3 and the second, after the block, shows 4. The file-scope x = 5 is shadowed throughout and never seen.

Discuss in Forum

Loading…

Topics

Other Subjects

Tags: Functions Questions and Answers || Functions MCQ Questions and Answers || Functions GK Questions and Answers || Functions GK MCQ Questions || Functions Multiple Choice Questions and Answers || Functions GK || GK on Functions || C Programming Questions and Answers || C Programming MCQ Questions and Answers || C Programming GK Questions and Answers || GK on C Programming

Functions Questions and Answers

Topics

Other Subjects

About Us

Stay informed about all important Dates & Notifications