complete guide to C++ Language

 

A complete guide to C++, covering key concepts, syntax, examples, important points, MCQs, and practical applications—very useful for exams (JKSSB, SSC, Bank PO), interviews, and real-world programming.

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✅ Introduction to C++

• C++ is an object-oriented programming language developed by Bjarne Stroustrup in 1983.

• It is an extension of the C language with added support for classes, objects, and OOP principles.

• C++ is used in game development, OS development, embedded systems, and more.

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📌 Key Features of C++

Feature	Description
Object-Oriented	Supports classes, objects, inheritance, etc.
Fast & Efficient	Close to hardware, faster than many high-level languages
Compiled Language	Converts code to machine code for execution
Platform Independent	Code can be compiled on multiple platforms
Rich Standard Library	Supports data structures, algorithms, etc.

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🧱 Structure of a C++ Program

cpp
#include <iostream>
using namespace std;

int main() {
    cout << "Hello, C++!";
    return 0;
}

🔍 Breakdown:

• #include <iostream> – Includes input/output functions

• using namespace std; – Allows using cout, cin without std::

• cout – Used for output

• cin – Used for input

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📚 Basic Concepts of C++

1. Data Types

cpp
int age = 20;
float salary = 56000.50;
char grade = 'A';

2. Input/Output

cpp
int num;
cin >> num;        // Input
cout << num;       // Output

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🔁 Control Structures

If-else

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

Switch

cpp
switch(choice) {
    case 1: cout << "One"; break;
    default: cout << "Invalid";
}

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🔄 Loops

For Loop

cpp
for(int i = 0; i < 5; i++) {
    cout << i;
}

While Loop

cpp
int i = 0;
while(i < 5) {
    cout << i;
    i++;
}

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📦 Functions

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

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🧠 Object-Oriented Concepts in C++

1. Class and Object

cpp
class Car {
public:
    string brand;
    void display() {
        cout << brand;
    }
};

int main() {
    Car c1;
    c1.brand = "BMW";
    c1.display();
}

2. Constructor

cpp
class A {
public:
    A() {
        cout << "Constructor called";
    }
};

3. Inheritance

cpp
class A {
public:
    void show() {
        cout << "Base";
    }
};

class B : public A {
};

int main() {
    B obj;
    obj.show();  // Output: Base
}

4. Polymorphism

• Compile-time: Function Overloading

• Runtime: Virtual Functions

cpp
class A {
public:
    virtual void display() {
        cout << "Base";
    }
};

class B : public A {
public:
    void display() override {
        cout << "Derived";
    }
};

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📁 File Handling in C++

cpp
#include <fstream>
ofstream file("data.txt");
file << "Hello C++";
file.close();

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🛠️ Practical Applications of C++

Area	Example/Use
Game Development	Unity, Unreal Engine use C++
Operating Systems	Windows, Mac kernels include C++ components
Embedded Systems	Microcontroller software
Database Software	Oracle, MySQL partially written in C++
GUI Apps	Desktop apps using Qt framework

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📌 Important Points for Exams

• C++ supports OOP principles: Abstraction, Inheritance, Polymorphism, Encapsulation.

• Uses cin/cout for input/output instead of scanf/printf.

• .cpp is the default file extension.

• Includes STL (Standard Template Library) for algorithms, vectors, stacks, etc.

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🧪 Short Programs

1. Factorial Using Function

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

2. Palindrome Check

cpp
string s = "madam";
string rev = string(s.rbegin(), s.rend());
if (s == rev)
    cout << "Palindrome";

3. Check Prime Number

cpp
bool isPrime(int n) {
    for(int i = 2; i < n; i++)
        if(n % i == 0) return false;
    return true;
}

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❓ Frequently Asked MCQs

1. Who developed C++?
   a) Dennis Ritchie
   b) Bjarne Stroustrup ✅
   c) James Gosling
   d) Guido van Rossum

2. Which is not a feature of C++?
   a) Object-Oriented
   b) Platform Dependent ✅
   c) Fast
   d) Supports Pointers

3. What is ‘class’ in C++?
   a) A loop
   b) A function
   c) A blueprint of an object ✅
   d) A header file

4. Which of the following is used for input in C++?
   a) scanf
   b) input
   c) cin ✅
   d) printf

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🎯 Conclusion

C++ is a powerful, fast, object-oriented language that combines low-level features of C with the modern features of OOP. It’s widely used in competitive programming, system design, and software development.