🧮 C++ Variables

🔍 Why Variables Matter

Variables are like containers that store data in your program. Whether you're keeping track of a user’s score in a game or storing input from a user, you’ll need variables to make your program dynamic and functional.

In C++, you must declare a variable before using it, meaning you have to tell the program what type of data the variable will hold.

---

📦 Syntax of Declaring Variables

type variableName = value;

✨ Example:

int age = 20;
string name = "Soumik";
float pi = 3.14;

---

🧠 Common Data Types

🔸 Note: To use stringYou must include the <string> header.

---

💡 Examples in Action

🔢 Declaring and Printing Variables

#include <iostream>
#include <string>
using namespace std;

int main() {
    int age = 20;
    string name = "Soumik";
    float favNumber = 3.14;

    cout << "Hi, I am " << name << ". I am " << age << " years old and my favorite number is " << favNumber << "." << endl;
    return 0;
}

🖨️ Output:

Hi, I am Soumik. I am 20 years old and my favorite number is 3.14.

---

🚫 Common Mistakes

❌ Using undeclared variables

cout << score;  // ❌ Error: 'score' was not declared

❌ Wrong data types

int pi = 3.14;   // ❌ Data loss; should be float

❌ Missing headers

string name = "Soumik"; // ❌ Requires #include <string>

---

✅ Best Practices

• Use meaningful variable names: userAge is better than x.

• Stick to one variable per line for readability.

• Always initialize your variables to avoid garbage values.

• Use const for values that don’t change (e.g., const float pi = 3.14;).

---

💼 Task for You

🔧 Task:
Write a C++ program that declares variables for:

• Your name (string)

• Your age (int)

• Whether you're currently learning C++ (bool)

Then print a sentence using all three variables.

💡 Sample Output:

Hi, I’m Soumik. I’m 20 years old. Am I learning C++? 1

(Note: 1 means true in boolean output)

🧠 Challenge:
Try using std::cout and std::endl instead of using namespace std;.

---

🎯 What's Next?

Now that you’ve learned how to declare and use variables, you’re ready to start accepting input from users! In the next post, we’ll dive into the cin statement and learn how to build interactive C++ programs.

📍Next up: Part 4 – C++ Input Syntax

---

✨ Follow the Series

This post is part of the C++ Zero to Hero blog series — your one-stop guide to learning C++ from scratch. Whether you're aiming for your first job, preparing for programming contests, or just passionate about learning, this series is for you.

Let’s grow together, one blog at a time! 💻✨