C++ Quiz on Mixed Topics Set 3 | C++ Interview Quiz | C++ Interview Questions

Posted by Parveen(Hoven),
Aptitude Trainer and Software Developer

Quiz Questions

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Question 1

What is the output ?

void main()
{

    int *j;

    {

        int i=10;

        j=&i;

    }

    printf("%d",*j);

}

Garbage value

Compiler Error

Linker Error

Soln.
Ans: B

The variable i is a block level variable and the visibility is inside that block only. But thelifetime of i is lifetime of the function so it lives upto the exit of main function. Since thei is still allocated space, *j prints the value stored in i since j points i.

Question 2

What happens ?

int main()
{

    int *a, i;

    a = (int*)malloc(SIZE*sizeof(int));

    /*Statement 1*/
    for (i=0; i<SIZE; i++)
    {

        *(a + i) = i * i;

    }

    /*Statement 2*/
    for (i=0; i<SIZE; i++)
    {

        printf("%d\n", *(a++));

    }

    /*Statement 3*/
    free(a);

    return 0;

}

Statement 1 causes a runtime error

Statement 2 causes a runtime error

Statement 3 causes a runtime error

No Error occurs at runtime

Soln.
Ans: C

free(a) causes error because 'a' has changed to a location[in Statement 2] that was not allocated with malloc. so 'free' causes a runtime error.

Question 3

What will be output if you will compile and execute the following c code?

int main()
{

    int i=320;

    char *ptr=(char *)&i;

    printf("%d",*ptr);

    return 0;

}

320

Compiler Error

Soln.
Ans: C

As we know size of int data type is two byte while char pointer can pointer one byte at time.Memory representation of int i=320

So char pointer ptr is pointing to only first byte as shown above figure.*ptr i.e. content of first byte is 01000000 and its decimal value is 64.

Question 4

Which lines of the following program will be printed ?

int main ()
{

    int i = 9;

    if (i -= 9)
    {

        /* Line 1 */
        cout << "Inside first 'if'" << endl;

    }

    if (i += 9)
    {

        /* Line 2 */
        cout << "Inside second 'if'" << endl;

    }

}

Line 1 only will be printed

Line 1 as well as Line 2 will be printed

Line 2 only will be printed

None will be printed

Soln.
Ans: C

Line 2 only will be printed

Question 5

What is the output

int main ()
{

    int x = 1;

    if (x--)
    printf ("X");

    --x;

    else
    {

        printf ("Y");

    }

    return 0;

}

Error

Soln.
Ans: D

The statement

--x;

comes just before 'else' which is illegal. Since no braces have been used, the above code is same as

int main ()
{

    int x = 1;

    if (x--)
    {

        printf ("X");

    }

    ERROR → --x;

    else
    {

        printf ("Y");

    }

    return 0;

}

Question 6

What is the output?

int main()
{

    int cnt = 5, a;

    do {
    a /= cnt;

} while (cnt --);

printf ("%d\n", a);

return 0;

}

Runtime error or Garbage

None of the above

Soln.
Ans: A

Self-Explanatory

Question 7

Consider the code below

int MyFunction(int x)
{

    int g = 0;

    g = x;

}

Here the function MyFunction

accepts one argument and returns an int

accepts one argument and returns nothing

accepts no arguments and returns nothing

accepts two arguments and returns something

Soln.
Ans: A

accepts one argument and returns an int, the function accepts an int argument by value and returns an int by value.

Question 8

What will be output if you will compile and execute the following c code?

int main()
{

    char c='\08';

    printf("%d",c);

    return 0;

}

'8'

undefined

Soln.
Ans: D

There is no octal number 8.

Question 9

void afunc(int x, int y)
{

    int g = 0;

    g = x;

}

Which of the following is/are correct ?

x is passed by reference and y is also passed by reference

x is passed by reference and y is passed by value

x is passed by value and y is also passed by value

x is passed by value and y is passed by reference

Soln.
Ans: C

x is passed by value and y is also passed by value

Question 10

What is the output?

int main()
{

    int i, j = 2;

    printf ("%d\n", i);

    printf ("%d\n", j);

    return 0;

}

Garbage
2

Garbage
Garbage

0
2

0
Garbage

Soln.
Ans: A

Self Explanantory

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