Why pointers are needed in C++ - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a pointer to an integer.

C++

int x = 10;
int * [1] = &x;

Drag options to blanks, or click blank then click option'

Ap

B*p

C&p

Dp*

Attempts:

3 left

💡 Hint

Common Mistakes

Using '*' in the variable name instead of in the type declaration.

We declare a pointer variable by specifying its name, here p. The asterisk (*) is used when defining the pointer type, not in the variable name.

2fill in blank

medium

Complete the code to access the value pointed to by the pointer.

C++

int x = 20;
int *p = &x;
int y = [1]p;

Drag options to blanks, or click blank then click option'

A*

B->

C&

D%

Attempts:

3 left

💡 Hint

Common Mistakes

Using '&' instead of '*' to access the value.

The asterisk (*) operator is used to dereference a pointer, which means accessing the value stored at the address the pointer holds.

3fill in blank

hard

Fix the error in the code to correctly assign the pointer.

C++

int x = 30;
int *p;
p = [1]x;

Drag options to blanks, or click blank then click option'

Ap

Bx

C*x

D&x

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning the value instead of the address to the pointer.

To assign a pointer to the address of a variable, use the address-of operator '&'.

4fill in blank

hard

Fill both blanks to create a pointer to a pointer and access the original value.

C++

int x = 40;
int *p = &x;
int **pp = [1];
int y = [2]pp;

Drag options to blanks, or click blank then click option'

A&p

B*pp

C**pp

Dp

Attempts:

3 left

💡 Hint

Common Mistakes

Using single dereference when double is needed.

Assigning pointer value instead of its address.

To create a pointer to a pointer, assign the address of the first pointer using '&p'. To access the original value, dereference twice using '**pp'.

5fill in blank

hard

Fill all three blanks to create a dynamic array, assign values, and access an element.

C++

int *arr = new int[[1]];
arr[0] = [2];
int first = arr[[3]];

Drag options to blanks, or click blank then click option'

A5

B10

C0

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong index to access array element.

Assigning value to wrong index.

We create a dynamic array of size 5, assign 10 to the first element (index 0), and access that element.