C++ is an incredibly versatile and powerful programming language that serves as the foundation for learning programming concepts. Today, we will cover the essentials of output and variables in C++, including printing, working with data types, operators, and the rules of naming variables. Let’s dive into the theory with practical examples!

1. Basic Printing in C++

To output data to the console in C++, we use the cout stream, which is part of the iostream library. The \n escape sequence is used to move to a new line after printing, ensuring clean formatting. Another way to achieve the same effect is by using endl.

Code Example:

#include <iostream>
using namespace std;

int main() {
    cout << "Hello, World!\n"; // Prints text with a new line
    cout << "Learning C++ is fun!\n";

    // Printing numbers and operations
    cout << 5 << "\n";          // Outputs 5
    cout << 3 + 2 << "\n";      // Outputs 5
    cout << 10 - 7 << "\n";     // Outputs 3

    return 0;
}

Explanation: The cout operator works by pushing output to the console using <<. Any text enclosed in double quotes (" ") is printed as-is, while numeric calculations or variables are evaluated and their values are displayed.

2. Variables and Printing Variables

Variables are containers for storing data that can be reused and manipulated. They make programs dynamic and efficient. Each variable has a data type that determines the kind of value it can hold:

• int: Stores integers like 1, -10, 42
• float: Stores decimal values like 3.14, -0.5
• bool: Stores true or false values
• char: Stores single characters like 'A', 'z'

Code Example:

#include <iostream>
using namespace std;

int main() {
    int age = 20;
    float height = 5.9;
    bool isStudent = true;
    char grade = 'A';

    // Printing variables
    cout << "Age: " << age << "\n";
    cout << "Height: " << height << "\n";
    cout << "Student status (1 for true, 0 for false): " << isStudent << "\n";
    cout << "Grade: " << grade << "\n";

    // Performing operations
    int x = 10, y = 5;
    cout << "Addition: " << x + y << "\n";
    cout << "Subtraction: " << x - y << "\n";
    cout << "Multiplication: " << x * y << "\n";
    cout << "Division: " << x / y << "\n";

    return 0;
}

Explanation: Variables allow us to store data temporarily in memory. Each data type has its specific purpose. For instance, int is used for whole numbers, while float is for decimal values. By combining variables with operators (+, -, *, /), we can perform calculations.

3. Modulus, Increment, and Decrement Operators

These operators are essential for working with numbers in C++:

• Modulus (%): Returns the remainder when one number is divided by another.
• Increment (++): Increases a variable’s value by 1.
• Decrement (--): Decreases a variable’s value by 1.

Code Example:

#include <iostream>
using namespace std;

int main() {
    int a = 10, b = 3;

    // Modulus operator
    cout << "10 % 3 = " << a % b << "\n";  // Outputs 1

    // Increment and Decrement
    a++;  // Increment a by 1 (a becomes 11)
    cout << "After increment, a = " << a << "\n";
    a--;  // Decrement a by 1 (a becomes 10)
    cout << "After decrement, a = " << a << "\n";

    return 0;
}

Explanation: The % operator is handy when you need to calculate remainders (e.g., checking divisibility). The increment and decrement operators are shorthand for adding or subtracting 1, making your code cleaner and more efficient.

4. Variable Naming Rules

When naming variables in C++, follow these rules:

• Variable names must begin with a letter or underscore (e.g., _myVar).
• They cannot contain spaces or special characters.
• Variable names are case-sensitive (e.g., age and Age are different).
• They cannot be the same as reserved keywords (e.g., int, return).

5. Comments in C++

Comments are used to explain your code or temporarily disable certain lines. They are ignored by the compiler. C++ supports two types of comments:

• Single-line comments: Use // to comment out one line.
• Multi-line comments: Enclose text in /* and */.

Code Example:

#include <iostream>
using namespace std;

int main() {
    // This is a single-line comment
    cout << "Single-line comments are handy!" << "\n";

    /* This is a 
       multi-line comment */
    cout << "Multi-line comments span multiple lines." << "\n";

    return 0;
}

Explanation: Comments make your code more readable and help other developers understand your logic. Always strive to add meaningful comments to your code.

Conclusion

Getting started with output and variables is crucial for any C++ programmer and its the most basic thing that everyone learns. These very basic and fundamental concepts in future will form the building blocks of more advanced programming techniques and softwares. 

With practice, you’ll soon be able to write efficient and well-structured C++ programs! Don't worry, its just a starting point, you just need to learn, create, and publish.