Key Concepts

Review core concepts you need to learn to master this subject

References

Pass-By-Reference

const Reference

Memory Address

Pointers

Dereference

References

int &sonny = songqiao;

In C++, a reference variable is an alias for another object. It is created using the & sign. Two things to note:

  1. Anything done to the reference also happens to the original.
  2. Aliases cannot be changed to alias something else.
References and Pointers
Lesson 1 of 1
  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 …
    Start
  2. 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…
    Start
  3. 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…
    Start
  4. 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 …
    Start
  5. 5
    Memory Address
    So we haved 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…
    Start
  6. 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 …
    Start
  7. 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…
    Start
  8. 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…
    Start
  9. 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 -…
    Start

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