C++ Programming Language: Complete Guide with Commands, Examples, and Applications

Introduction to C++

C++ is a powerful, high-level programming language developed by Bjarne Stroustrup in 1983 as an extension of the C language. It introduced object-oriented programming (OOP) concepts like classes and objects, making it suitable for large-scale software development. C++ combines the efficiency of C with advanced programming features, making it one of the most widely used languages in software, gaming, and systems development.

History and Evolution of C++

• 1979: Bjarne Stroustrup starts developing “C with Classes.”
• 1983: Officially named C++, introducing object-oriented features.
• 1985: First commercial release of C++ compiler.
• 1990: ANSI/ISO standardization begins.
• 1998: C++98 standard released.
• 2011: C++11 introduces modern features like auto, nullptr, and lambda expressions.
• 2014 & 17: C++14 and C++17 add further improvements.
• 2020: C++20 introduces concepts, ranges, and modules for modern programming.

Features of C++

• Supports procedural, object-oriented, and generic programming.
• High performance and efficiency similar to C.
• Supports classes, objects, inheritance, polymorphism, encapsulation, and abstraction.
• Rich Standard Template Library (STL) for data structures and algorithms.
• Portable and flexible for system and application programming.

Structure of a C++ Program

#include <iostream>  // Standard input-output library
using namespace std;

int main() {
    cout << "Hello, C++" << endl;  // Output statement
    return 0;                       // Exit status
}

• #include <iostream> → Includes the input-output stream library.
• using namespace std; → Avoids typing std:: before standard functions.
• cout → Prints output on the console.
• endl → Moves cursor to the next line.

Basic Syntax and Commands

• Printing output:

cout << "Welcome to C++ programming";

• Reading input:

int age;
cin >> age;

• Comments:

// Single-line comment
/* Multi-line comment */

Data Types & Variables

C++ has similar data types as C with some additions:

• Basic types: int, float, double, char, bool
• Derived types: arrays, pointers, references
• User-defined types: classes, structs, enums

Example:

int x = 10;
float price = 99.5;
char grade = 'A';
bool isActive = true;

Operators in C++

• Arithmetic: + - * / %
• Relational: == != < > <= >=
• Logical: && || !
• Assignment: = += -= *= /=
• Increment/Decrement: ++ --
• Additional C++ operators: :: (scope resolution), -> (pointer to member), new & delete

Example:

int a = 5, b = 3;
cout << "Sum: " << a + b << endl;

Control Statements (if, switch, loops)

• If-Else:

if(age >= 18) {
    cout << "Adult";
} else {
    cout << "Minor";
}

• Switch:

switch(day) {
    case 1: cout << "Monday"; break;
    case 2: cout << "Tuesday"; break;
    default: cout << "Invalid"; 
}

• Loops:

for(int i=1; i<=5; i++)
    cout << i << " ";

int j=1;
while(j<=5) {
    cout << j << " ";
    j++;
}

int k=1;
do {
    cout << k << " ";
    k++;
} while(k<=5);

Functions in C++

#include <iostream>
using namespace std;

int add(int a, int b) {
    return a + b;
}

int main() {
    int result = add(10, 20);
    cout << "Sum = " << result;
    return 0;
}

Object-Oriented Programming in C++

• Class and Object:

#include <iostream>
using namespace std;

class Student {
public:
    string name;
    int age;

    void display() {
        cout << "Name: " << name << ", Age: " << age << endl;
    }
};

int main() {
    Student s1;
    s1.name = "Alice";
    s1.age = 20;
    s1.display();
    return 0;
}

• Inheritance, Polymorphism, Encapsulation, and Abstraction are key OOP features.

Arrays, Strings, and Pointers

• Array:

int arr[5] = {1,2,3,4,5};

• String (C++ STL):

#include <string>
string name = "C++ Language";
cout << name;

• Pointer:

int x = 10;
int* ptr = &x;
cout << *ptr; // 10

File Handling in C++

#include <fstream>
using namespace std;

int main() {
    ofstream outfile("example.txt");
    outfile << "Hello File Handling in C++";
    outfile.close();
    return 0;
}

• ifstream → Read files
• ofstream → Write files
• fstream → Read & write

Memory Management

C++ provides dynamic memory allocation:

int* ptr = new int;  // Allocate memory
*ptr = 25;
cout << *ptr;
delete ptr;          // Free memory

• new → Allocates memory
• delete → Frees memory

Advantages & Limitations

• Advantages:
  • High performance, object-oriented, STL support.
  • Portable across platforms.
  • Supports both procedural and OOP paradigms.
• Limitations:
  • Complex syntax for beginners.
  • Manual memory management.
  • Larger programs may be harder to debug.

Real-Life Applications

• Software and game development
• Operating systems and compilers
• Real-time simulations
• GUI-based applications
• Banking and enterprise software

Sample Programs

• Factorial Using Function:

#include <iostream>
using namespace std;

int factorial(int n) {
    if(n == 0) return 1;
    return n * factorial(n-1);
}

int main() {
    int num;
    cin >> num;
    cout << "Factorial = " << factorial(num);
    return 0;
}

• Class Example with Inheritance:

#include <iostream>
using namespace std;

class Person {
public:
    string name;
};

class Student : public Person {
public:
    int roll;
    void display() { cout << name << " - " << roll; }
};

int main() {
    Student s;
    s.name = "Bob";
    s.roll = 101;
    s.display();
    return 0;
}

Conclusion

C++ is a versatile and powerful language suitable for both beginner programmers and advanced developers. Its combination of procedural and object-oriented programming, along with high performance, makes it ideal for software development, gaming, and systems programming. Mastering C++ builds a strong foundation for learning modern programming languages and creating efficient, scalable applications.