Learn C++: Course OverviewCourse Overview

References & Pointers

References and pointers are some of the most powerful features in C++; they allow programmers to directly manipulate memory.

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Key Concepts

Review core concepts you need to learn to master this subject

const Reference

Pointers

References

Memory Address

Dereference

Pass-By-Reference

`const` Reference

int triple(int const &i) {

  return i * 3;

}

In C++, pass-by-reference with const can be used for a function where the parameter(s) won’t change inside the function.

This saves the computational cost of making a copy of the argument.

References and Pointers

Lesson 1 of 1

1
Introduction
A computer’s memory is a sequence of bytes. We can number the bytes from 0 to the last one. Each number, known as an address, represents a location in the …
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2
References
In C++, a reference variable is an alias for something else, that is, another name for an already existing variable. So suppose we make Sonny a reference to someone named Songqiao. You can refe…
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3
Pass-By-Reference
So what’s a good use case for references? Let’s take a look. Previously, when we passed parameters to a function, we used normal variables and that’s known as pass-by-value. But because the vari…
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4
Pass-By-Reference with Const
Remember const? The const keywords tells the compiler that we won’t change something. For example, in the following code, we are telling the compiler that the double variable pi will stay at 3.14 …
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5
Memory Address
So we have learned about references (aliases), which are created by using the & symbol in a variable declaration. But the & sign can have another meaning. The “address of” operator, &, is used to …
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6
Pointers
In C++, a pointer variable is mostly the same as other variables, which can store a piece of data. Unlike normal variables, which store a value (such as an int, double, char), a pointer stores a …
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7
Dereference
So now we learned what a pointer is and how to create one, but is there a way to obtain the value pointed to by the pointer? The asterisk sign * a.k.a. the dereference operator is used to obtain t…
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8
Null Pointer
When we declare a pointer variable like so, its content is not intialized: int* ptr; In other words, it contains an address of “somewhere”, which is of course not a valid location. This is [dang…
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9
Review
Congratulations! You have officially done it. 🎉🎉🎉 In this lesson, you have learned: - References - Pass-by-reference - Pass-by-reference with const - Memory addresses and how to access them -…
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