Introduction to C++

A Quick History of C++

C++ began its life in the early 1980s at Bell Labs, the same research center that gave us the C language. A Danish computer scientist named Bjarne Stroustrup wanted to add features from another language he liked (Simula) to the power and flexibility of C. His goal was to make it easier to manage large, complex software projects.

The new language was first called "C with Classes." This name was practical but not very catchy. It was later renamed C++, a clever nod to the ++ increment operator in C, which adds one to a value. The name implies that C++ is a step up from C.

Since then, C++ has been formally standardized and continues to evolve. An international committee releases new versions every few years (like C++11, C++14, C++17, and C++20), adding modern features that keep the language powerful and relevant for today's programming challenges.

What Makes C++ Special?

C++ is known for its performance. It's a compiled language, which means your code gets translated directly into machine instructions that a computer's processor can execute very quickly. This makes it a top choice for tasks where speed is critical, like video game engines, financial trading systems, and operating systems.

It also gives the programmer a high level of control over system resources, especially memory. While this adds some complexity, it allows for fine-tuned optimization that isn't possible in many other languages. C++ also comes with a rich Standard Library that provides a host of tools for tasks like working with collections of data, handling text, and performing mathematical operations.

Your First C++ Program

Let's look at the traditional first program for any new language: one that simply prints "Hello, World!" to the screen. It might look a little complex at first, but each part has a specific job.

#include <iostream>

// This is the main function where the program starts
int main() {
    // Print text to the console
    std::cout << "Hello, World!";
    
    // Signal that the program finished successfully
    return 0;
}

Here’s a breakdown of what’s happening:

#include <iostream>: This line tells the compiler to include the iostream file. This file contains code that allows us to get input from the user and display output to the screen.
int main(): This is the main function. Every C++ program must have a main() function, as it’s the starting point for execution. When you run your program, the code inside these curly braces {} is what gets executed first.
std::cout << "Hello, World!";: This is the line that does the printing. std::cout is the standard character output stream, and the << operator is used to send the text "Hello, World!" to it.
return 0;: This tells the operating system that the program has finished and everything went okay. A return value of 0 means success.

Notice the semicolon (;) at the end of the std::cout and return lines. In C++, semicolons are like periods in English. They mark the end of a statement.

Variables and Constants

Programs need to store information while they run. This is done using variables. A variable is just a named piece of memory where you can store a value. Think of it like a labeled box where you can put something, take it out, or replace it with something else.

To create a variable in C++, you must declare it by giving it a type and a name. For example, to store a whole number:

// Declares an integer variable named 'score'
int score;

// Assigns the value 100 to 'score'
score = 100;

// You can also declare and assign in one step
int newScore = 200;

Sometimes, you have a value that should never change while the program is running, like the value of Pi or the number of months in a year. For this, you use a constant. You declare a constant using the const keyword. Once set, its value is locked.

const double PI = 3.14159;
const int MONTHS_IN_YEAR = 12;

// This would cause an error:
// PI = 4.0;

Using constants makes your code safer and easier to understand, as it clearly marks values that are not meant to be modified.

Now, let's test your knowledge of these foundational concepts.

Quiz Questions 1/6

Who is credited with the creation of C++?

Quiz Questions 2/6

The name 'C++' is a clever reference to what feature from the C language?