Questions and answers for exam Preparation

MCQs

Total Questions : 10

Pick out the correct statement.

The NULL pointer dereference occurs where a pointer that is expected to be a valid address but instead is equal to NULL.
The NULL pointer dereference occurs where a pointer that is expected to be a valid address but instead is equal to memory address.
both a & b
none of the mentioned

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Answer: Option A. -> The NULL pointer dereference occurs where a pointer that is expected to be a valid address but instead is equal to NULL.

None.

Question 2.

What does the dereference operator will return?

rvalue equivalent to the value at the pointer address.
lvalue equivalent to the value at the pointer address.
it will return nothing
none of the mentioned

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Answer: Option B. -> lvalue equivalent to the value at the pointer address.

It operates on a pointer variable, and returns an l-value equivalent to the value at the pointer address.

Question 3.

What is the output of this program?

1.
#include
2.
using namespace std;
3.
int main()
4.
{
5.
double arr[] = {5.0, 6.0, 7.0, 8.0};
6.
double *p = (arr+2);
7.
cout

rvalue equivalent to the value at the pointer address.
lvalue equivalent to the value at the pointer address.
it will return nothing
none of the mentioned

Discuss Question

Answer: Option B. -> lvalue equivalent to the value at the pointer address.

Answer:(a)
Explanation:In this program, We are printing the values that are pointed by pointer and also the dereference oerator.
Output:
$ g++ def5.cpp
$ a.out
7
0xbf99fc98
8
5
14

Question 4.

What is the output of this program?

1.
#include
2.
using namespace std;
3.
int main()
4.
{
5.
int x = 9;
6.
int* p = &x;
7.
cout

4
2
Depends on compiler
none of the mentioned

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Answer: Option C. -> Depends on compiler

The size of a datatype mainly depends on complier only.
Output:
$ g++ def3.cpp
$ a.out
4

Question 5.

What is the output of this program?

1.
#include
2.
using namespace std;
3.
int main ()
4.
{
5.
int a;
6.
int * ptr_b;
7.
int ** ptr_c;
8.
a = 1;
9.
ptr_b = &a;
10.
ptr_c = &ptr_b;
11.
cout

4
2
Depends on compiler
none of the mentioned

Discuss Question

Answer: Option C. -> Depends on compiler

Answer: (a)
Explanation:In this program, We are printing the values and memory address
by using the pointer and derefernce operator.
Output:
$ g++ def2.cpp
$ a.out
1
1
0xbffc9924
1