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1. Introduction & Compilation

C++ is a very powerful, statically typed, object-oriented programming language. Unlike Python or Java, C++ is compiled directly into machine code, making it extremely fast.

You need a compiler like G++ (on Linux) or MinGW (on Windows). The standard 'Hello World' code uses the `iostream` library.

#include <iostream>

int main() {
    // std::cout is the object for printing to the console
    std::cout << "Hello, C++!" << std::endl;
    return 0;
}

# Compile the code
g++ main.cpp -o program

# Run the program
./program

2. Variables & Data Types

Variable declarations in C++ MUST include their data type. Common primitive types are `int`, `double` (for decimals), `char` (character), and `bool` (true/false).

Use `const` to make a variable a constant (it cannot be changed).

#include <string>

int main() {
    int age = 25;
    double price = 10.99;
    bool isComplete = true;
    std::string name = "Budi"; // String is part of the standard library

    const double PI = 3.14159;
    // PI = 3; // This will cause an error (because of const)
}

3. Control Flow (If, For, While)

Control flow syntax in C++ is identical to Java or C. It uses `if-else` and `switch` for conditionals, and `for` and `while` for loops.

int num = 10;

if (num > 5) {
    std::cout << "Greater than 5";
} else {
    std::cout << "5 or smaller";
}

// Standard 'for' loop
for (int i = 0; i < 3; i++) {
    std::cout << i << std::endl;
}

4. Functions

Functions in C++ must be defined with a return type. If a function returns nothing, use `void`.

In C++, there is often a separation between Declaration (in a `.h` file) and Definition (in a `.cpp` file), though for simple programs they can be in one file.

// Function declaration & definition
int add(int a, int b) {
    return a + b;
}

void greet(std::string name) {
    std::cout << "Hello, " << name;
}

int main() {
    int result = add(5, 3);
    greet("Alex");
}

5. Pointers & References

This is the most important concept in C++. A Pointer is a variable that stores the memory address of another variable.

1. `&` (Address-of): Gets the memory address. `int x = 10; int* ptr = &x;`

2. `*` (Dereference): Gets the value *at* that address. `std::cout << *ptr; // Will print 10`

Pointers are crucial for manual memory management (`new` and `delete`) and for 'pass-by-reference'.

// This function changes the original 'value'
void addTen(int* numPtr) {
    *numPtr = *numPtr + 10;
}

int main() {
    int myValue = 20;
    addTen(&myValue); // Send its address
    std::cout << myValue; // Output: 30
}

6. OOP: Classes & Objects

C++ is an OOP language. You use the `class` keyword to create a 'blueprint'. By default, all properties in a class are `private`.

`public:`: Can be accessed from outside. `private:`: Can only be accessed from within the class.

class Dog {
private:
    int age;

public:
    // Constructor
    Dog(int startAge) {
        age = startAge;
    }

    // Method
    void bark() {
        std::cout << "Woof!";
    }
};

int main() {
    Dog myDog(5); // Create an object
    myDog.bark();
    // myDog.age = 10; // Error! 'age' is private
}

7. STL (Standard Template Library)

Don't create your own data structures. C++ provides the STL, a rich collection of templates.

1. `std::vector`: Dynamic array (most common).

2. `std::map`: Key-value store (like a Dictionary).

3. `std::string`: Text (you've already used it).

#include <vector>
#include <map>
#include <string>

int main() {
    // Vector (Dynamic array)
    std::vector<int> numbers;
    numbers.push_back(10);
    numbers.push_back(20);

    // Map (Key-Value)
    std::map<std::string, int> scores;
    scores["Alice"] = 100;
}

Practice Set

Reinforce basic C++ concepts, from syntax, pointers, to OOP.

Question #1 - C++ Introduction

Which stream object is used to print output to the console in C++?

Question #2 - Variables & Data Types

Which is the correct way to declare a constant (fixed value) in modern C++?

Question #3 - Pointers

Which operator is used to get the memory address of a variable?

Question #4 - Pointers

Which operator is used to access the value at a memory address (dereferencing a pointer)?

Question #5 - OOP

In C++, how does a Class (e.g., 'Sedan') inherit from another Class (e.g., 'Car')?

Question #6 - OOP

The `private` access modifier means...

Question #7 - STL

Which data structure in the C++ Standard Template Library (STL) functions as a dynamic array (like ArrayList in Java)?

Final Exam

Test your C++ knowledge, including memory management and the STL.