Key Concepts
Review core concepts you need to learn to master this subject
Variable in memory.
Variable in memory.
A variable in a computer programming language refers to a storage location in memory. Variables are denoted by a name. Value of a variable can be changed.
- 1The “Hello World!” program just writes to the screen. It does not read anything, calculate anything, or allow for user input. That’s no fun! Real programs tend to produce results based on some in…
- 2“Every variable in C++ must be declared before it can be used!” Suppose we are building a game and we want to keep track of a player’s score that goes from 0 to 10. We need a variable! Before w…
- 3After we declare a variable, we can give it a value! Suppose that we have declared an int variable called score, to set it to 0, we can simply write: score = 0; - The score is the name of the v…
- 4We can both declare and assign a value to a variable in a single initialization statement. Suppose we have these two lines: // Declare a variable int score; // Initialize a variable score = 0; …
- 5Computers are incredible at doing calculations. Now that we have declared variables, let’s use them and arithmetic operators to calculate things! Here are some arithmetic operators: - + additio…
- 6Now that we have outputted a variable and have also outputted things using multiple couts. Let’s take a closer look at cout again. If we have the code below: int age = 28; std::cout << “Hello, …
- 7Like we mentioned in the introduction, another way to assign a value to a variable is through user input. A lot of times, we want the user of the program to enter information for the program. We h…
- 8Now that we’ve learned about the basics of variables and cin, let’s write a program! The mad scientist Kelvin has mastered predicting the weather in his mountain-side meteorology lab. Recently, K…
- 9Let’s go back to the temperature.cpp that we wrote. This time, instead of giving tempf a value of the current temperature in New York: tempf = 83; Let’s ask the user what the temperature is …
- 10You made it to the end of this lesson! High five! Here is a review of the lesson: - A variable represents a particular piece of your computer’s memory that has been set aside for you to use to …
What you'll create
Portfolio projects that showcase your new skills
Dog Years
Dogs have ages that don't quite work like ours. This can be a little ruff when you want to know how old your dog would be if he/she is a human. Don't fret — build a dog-age-converting program to translate your dog's age into human years!
Quadratic Formula
Write a C++ program that solves the quadratic equation.
Piggy Bank
You just returned from a trip in South America and you came back with three different kinds of currencies. Let's convert them to USD!
How you'll master it
Stress-test your knowledge with quizzes that help commit syntax to memory