Pointers MCQ in C++ - Sanfoundry

This section on C++ aptitude questions and answers focuses on “Pointers”. One shall practice these aptitude questions to improve their C++ programming skills needed for various interviews (campus interviews, walk-in interviews, company interviews), placements, entrance exams, aptitude tests and other competitive exams. These questions can be attempted by anyone focusing on learning C++ programming language. They can be a beginner, fresher, engineering graduate or an experienced IT professional. Our C++ questions come with the detailed explanation of the answers which helps in better understanding of C++ concepts.

Here is a listing of C++ aptitude questions on “Pointers” along with answers, explanations and/or solutions:

1. What does the following statement mean?

int (*fp)(char*)

a) pointer to a pointer
b) pointer to an array of chars
c) pointer to function taking a char* argument and returns an int
d) function taking a char* argument and returning a pointer to int
View Answer

Answer: c
Explanation: The (*fn) represents a pointer to a function and char* as arguments and returning int from the function. So according to that, the above syntax represents a pointer to a function taking a char* as an argument and returning int.

2. The operator used for dereferencing or indirection is ____
a) *
b) &
c) ->
d) –>>
View Answer

Answer: a
Explanation: * is used as dereferencing operator, used to read value stored at the pointed address.

3. Choose the right option.

string* x, y;

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a) x is a pointer to a string, y is a string
b) y is a pointer to a string, x is a string
c) both x and y are pointers to string types
d) y is a pointer to a string
View Answer

Answer: a
Explanation: * is to be grouped with the variables, not the data types.

4. Which one of the following is not a possible state for a pointer.
a) hold the address of the specific object
b) point one past the end of an object
c) zero
d) point to a type
View Answer

Answer: d
Explanation: A pointer can be in only 3 states a, b and c.

5. Which of the following is illegal?
a) int *ip;
b) string s, *sp = 0;
c) int i; double* dp = &i;
d) int *pi = 0;
View Answer

Answer: c
Explanation: dp is initialized int value of i.

6. What will happen in the following C++ code snippet?

```
   int a = 100, b = 200;
```
```
   int *p = &a, *q = &b;
```
```
   p = q;
```

a) b is assigned to a
b) p now points to b
c) a is assigned to b
d) q now points to a
View Answer

Answer: b
Explanation: Assigning to reference changes the object to which the reference is bound.

7. What will be the output of the following C++ code?

```
    #include <iostream>
```
```
    using namespace std;
```
```
    int main()
```
```
    {
```
```
        int a = 5, b = 10, c = 15;
```
```
        int *arr[ ] = {&a, &b, &c};
```
```
        cout << arr[1];
```
```
        return 0;
```
```
    }
```

a) 5
b) 10
c) 15
d) it will return some random number
View Answer

Answer: d
Explanation: Array element cannot be address of auto variable. It can be address of static or extern variables.

8. The correct statement for a function that takes pointer to a float, a pointer to a pointer to a char and returns a pointer to a pointer to a integer is ____________
a) int **fun(float**, char**)
b) int *fun(float*, char*)
c) int **fun(float*, char**)
d) int ***fun(*float, **char)
View Answer

Answer: c
Explanation: Function that takes pointer to a float, a pointer to a pointer to a char and returns a pointer to a pointer to a integer is int **fun(float*, char**).

9. What will be the output of the following C++ code?

```
    #include <iostream>
```
```
    using namespace std;
```
```
    int main()
```
```
    {
```
```
        char arr[20];
```
```
        int i;
```
```
        for(i = 0; i < 10; i++)
```
```
            *(arr + i) = 65 + i;
```
```
        *(arr + i) = '\0';
```
```
        cout << arr;
```
```
        return(0);
```
```
    }
```

a) ABCDEFGHIJ
b) AAAAAAAAAA
c) JJJJJJJJ
d) AAAAAAJJJJ
View Answer

Answer: a
Explanation: Each time we are assigning 65 + i. In first iteration i = 0 and 65 is assigned. So it will print from A to J.
$ g++ point1.cpp
$ a.out
ABCDEFGHIJ

10. What will be the output of the following C++ code?