Reference declaration in C++ - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a reference in C++?

A reference in C++ is an alias for another variable. It allows you to create a new name for an existing variable, so both names refer to the same memory location.

beginner

How do you declare a reference variable in C++?

You declare a reference by using the & symbol after the type. For example: int &ref = originalVariable; creates a reference named ref to originalVariable.

intermediate

Can a reference be changed to refer to another variable after initialization?

No, once a reference is initialized to a variable, it cannot be changed to refer to another variable. It always refers to the original variable it was bound to.

beginner

What happens if you modify a reference variable?

Modifying a reference variable changes the value of the original variable it refers to, because both names point to the same memory location.

intermediate

Why use references instead of pointers in C++?

References are safer and easier to use because they cannot be null and do not require dereferencing syntax. They provide a simpler way to alias variables without pointer complexity.

How do you declare a reference to an int variable named num?

A int &ref = num;

B int *ref = #

C int ref = #

D int &ref;

Option A correctly declares a reference named ref to the variable num.

Can a reference be null in C++?

A No, references must always refer to a valid variable.

B Only for pointer references.

C Only if initialized with nullptr.

D Yes, references can be null.

References must always refer to a valid variable and cannot be null.

What happens if you assign a new value to a reference variable?

A The reference starts pointing to a new variable.

B A new variable is created.

C The original variable's value changes.

D Compilation error.

Assigning a new value to a reference changes the value of the original variable it refers to.

Which symbol is used to declare a reference in C++?

A *

B &

C #

D %

The & symbol is used to declare a reference.

Can you declare a reference without initializing it?

A Only inside functions.

B Yes, references can be declared without initialization.

C Only for const references.

D No, references must be initialized when declared.

References must be initialized at the time of declaration.

Explain what a reference is in C++ and how it differs from a pointer.

Think about how you use a nickname for a friend instead of their full name.

Describe how to declare and use a reference variable in C++ with an example.

Show how to create a new name for an existing variable and change its value.