XOR Swap

XOR can be used to swap two integer values without using a third variable.

XOR का उपयोग बिना third variable के दो integer values को swap करने के लिए किया जा सकता है।

Complete Example — Swap Two Numbers Using XOR

#include <iostream>
using namespace std;

int main() {

    int a = 10;
    int b = 20;

    a = a ^ b;
    b = a ^ b;
    a = a ^ b;

    cout << "After swapping:" << endl;
    cout << "a = " << a << endl;
    cout << "b = " << b;

    return 0;
}

After swapping:
a = 20
b = 10

Note: XOR swap is generally demonstrated with integer values.

if Statement

The if statement executes a block of code when a given condition is true.

if statement तब code को execute करता है जब दी गई condition true होती है।

Complete Example

#include <iostream>
using namespace std;

int main() {

    int age = 20;

    if (age >= 18) {
        cout << "You are eligible.";
    }

    return 0;
}

You are eligible.

if-else Statement

The if-else statement executes one block when the condition is true and another block when it is false.

if-else statement में condition true होने पर एक block और false होने पर दूसरा block execute होता है।

Complete Example

#include <iostream>
using namespace std;

int main() {

    int number = 10;

    if (number > 0) {
        cout << "Positive number";
    }
    else {
        cout << "Negative number";
    }

    return 0;
}

Positive number

Nested if

A nested if means using one if statement inside another if statement.

Nested if का मतलब है एक if statement के अंदर दूसरा if statement का उपयोग करना।

Complete Example

#include <iostream>
using namespace std;

int main() {

    int age = 20;
    int id = 1;

    if (age >= 18) {

        if (id == 1) {
            cout << "Entry allowed";
        }

    }

    return 0;
}

Entry allowed

else-if Ladder

An else-if ladder is used to check multiple conditions one by one.

else-if ladder का उपयोग multiple conditions को एक-एक करके check करने के लिए किया जाता है।

Complete Example

#include <iostream>
using namespace std;

int main() {

    int marks = 75;

    if (marks >= 90) {
        cout << "Grade A+";
    }
    else if (marks >= 75) {
        cout << "Grade A";
    }
    else if (marks >= 60) {
        cout << "Grade B";
    }
    else if (marks >= 50) {
        cout << "Grade C";
    }
    else {
        cout << "Fail";
    }

    return 0;
}

Grade A

switch Statement

The switch statement is used to select one block of code from multiple choices.

switch statement का उपयोग multiple choices में से एक block of code को select करने के लिए किया जाता है।

Complete Example

#include <iostream>
using namespace std;

int main() {

    int day = 2;

    switch (day) {

        case 1:
            cout << "Monday";
            break;

        case 2:
            cout << "Tuesday";
            break;

        case 3:
            cout << "Wednesday";
            break;

        default:
            cout << "Invalid day";
    }

    return 0;
}

Tuesday

Note: The break statement stops the execution of the switch block.

for Loop

The for loop is used to execute a block of code repeatedly for a specific number of times.

for loop का उपयोग किसी code को एक निश्चित संख्या में बार-बार execute करने के लिए किया जाता है।

Complete Example

#include <iostream>
using namespace std;

int main() {

    for (int i = 1; i <= 5; i++) {
        cout << i << endl;
    }

    return 0;
}

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while Loop

The while loop repeatedly executes a block of code as long as the given condition is true.

while loop तब तक code को बार-बार execute करता है जब तक दी गई condition true रहती है।

Complete Example

#include <iostream>
using namespace std;

int main() {

    int i = 1;

    while (i <= 5) {

        cout << i << endl;

        i++;
    }

    return 0;
}

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do-while Loop

The do-while loop executes the code block at least once and then checks the condition.

do-while loop code block को कम से कम एक बार execute करता है और उसके बाद condition check करता है।

Complete Example

#include <iostream>
using namespace std;

int main() {

    int i = 1;

    do {

        cout << i << endl;

        i++;

    } while (i <= 5);

    return 0;
}

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Important: A do-while loop executes at least once, even when the condition is false initially.

Loop Comparison

break Statement

The break statement is used to stop the loop immediately.

break statement का उपयोग loop को तुरंत stop करने के लिए किया जाता है।

Example 1 — Stop Loop

#include <iostream>
using namespace std;

int main() {

    for (int i = 1; i <= 10; i++) {

        if (i == 5) {
            break;
        }

        cout << i << endl;
    }

    return 0;
}

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Example 2 — Break with while Loop

#include <iostream>
using namespace std;

int main() {

    int i = 1;

    while (i <= 10) {

        if (i == 4) {
            break;
        }

        cout << i << endl;
        i++;
    }

    return 0;
}

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Example 3 — Break with Number

#include <iostream>
using namespace std;

int main() {

    for (int i = 1; i <= 5; i++) {

        if (i == 3) {
            break;
        }

        cout << i << " ";
    }

    return 0;
}

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continue Statement

The continue statement skips the current iteration and moves to the next iteration.

continue statement current iteration को skip करके next iteration पर चला जाता है।

Example 1 — Skip Number 3

#include <iostream>
using namespace std;

int main() {

    for (int i = 1; i <= 5; i++) {

        if (i == 3) {
            continue;
        }

        cout << i << endl;
    }

    return 0;
}

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Example 2 — Skip Even Number

#include <iostream>
using namespace std;

int main() {

    for (int i = 1; i <= 5; i++) {

        if (i % 2 == 0) {
            continue;
        }

        cout << i << " ";
    }

    return 0;
}

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Example 3 — Skip Number 2

#include <iostream>
using namespace std;

int main() {

    int i = 0;

    while (i < 5) {

        i++;

        if (i == 2) {
            continue;
        }

        cout << i << " ";
    }

    return 0;
}

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Lambda Expressions

A lambda expression is a small anonymous function that can be created directly in C++ code.

Lambda Expression एक छोटा anonymous function है जिसे C++ code के अंदर directly बनाया जा सकता है।

Example 1 — Simple Lambda

#include <iostream>
using namespace std;

int main() {

    auto greet = []() {
        cout << "Hello C++";
    };

    greet();

    return 0;
}

Hello C++

Example 2 — Lambda with Parameters

#include <iostream>
using namespace std;

int main() {

    auto add = [](int a, int b) {
        return a + b;
    };

    cout << add(10, 20);

    return 0;
}

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Example 3 — Lambda with Variable

#include <iostream>
using namespace std;

int main() {

    int number = 10;

    auto square = [number]() {
        return number * number;
    };

    cout << square();

    return 0;
}

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Quick Revision

Functions Functions क्या हैं?

Example: Simple Function उदाहरण: Simple Function

#include <iostream>
using namespace std;

void greet() {
    cout << "Hello C++";
}

int main() {

    greet();

    return 0;
}

Hello C++

Function Declaration and Definition Function Declaration और Definition

Example: Declaration and Definition उदाहरण: Declaration और Definition

#include <iostream>
using namespace std;

// Function Declaration
void greet();

// Function Definition
void greet() {
    cout << "Welcome to C++";
}

int main() {

    greet();

    return 0;
}

Welcome to C++

Function Parameters Function Parameters

Example: Function with Parameters उदाहरण: Parameters वाला Function

#include <iostream>
using namespace std;

void add(int a, int b) {

    cout << "Sum = " << a + b;
}

int main() {

    add(10, 20);

    return 0;
}

Sum = 30

Return Value Return Value

Example: Function with Return Value उदाहरण: Return Value वाला Function

#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;
}

Sum = 30

Quick Revision Quick Revision

Call by Value Call by Value

Example: Call by Value उदाहरण: Call by Value

#include <iostream>
using namespace std;

void change(int x) {
    x = 20;
}

int main() {

    int a = 10;

    change(a);

    cout << "a = " << a;

    return 0;
}

a = 10

Call by Reference Call by Reference

Example: Call by Reference उदाहरण: Call by Reference

#include <iostream>
using namespace std;

void change(int &x) {
    x = 20;
}

int main() {

    int a = 10;

    change(a);

    cout << "a = " << a;

    return 0;
}

a = 20

Recursion Recursion

Example: Recursion उदाहरण: Recursion

#include <iostream>
using namespace std;

void count(int n) {

    if (n == 0)
        return;

    cout << n << endl;

    count(n - 1);
}

int main() {

    count(5);

    return 0;
}

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One-Dimensional Arrays One-Dimensional Arrays

Example: One-Dimensional Array उदाहरण: One-Dimensional Array

#include <iostream>
using namespace std;

int main() {

    int numbers[5] = {10, 20, 30, 40, 50};

    for (int i = 0; i < 5; i++) {
        cout << numbers[i] << endl;
    }

    return 0;
}

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Two-Dimensional Arrays Two-Dimensional Arrays

Example: Two-Dimensional Array उदाहरण: Two-Dimensional Array

#include <iostream>
using namespace std;

int main() {

    int numbers[2][2] = {
        {10, 20},
        {30, 40}
    };

    for (int i = 0; i < 2; i++) {

        for (int j = 0; j < 2; j++) {
            cout << numbers[i][j] << " ";
        }

        cout << endl;
    }

    return 0;
}

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Strings Strings

String Example 1: Store a Name String Example 1: Name Store करना

#include <iostream>
using namespace std;

int main() {

    string name = "Rahul";

    cout << "Name = " << name;

    return 0;
}

Name = Rahul

String Example 2: Store a Sentence String Example 2: Sentence Store करना

#include <iostream>
using namespace std;

int main() {

    string message = "I am learning C++";

    cout << message;

    return 0;
}

I am learning C++

String Example 3: Take String Input String Example 3: String Input लेना

#include <iostream>
using namespace std;

int main() {

    string name;

    cout << "Enter your name: ";
    cin >> name;

    cout << "Hello " << name;

    return 0;
}

Enter your name: Amit
Hello Amit

String Example 4: Find String Length String Example 4: String की Length निकालना

#include <iostream>
using namespace std;

int main() {

    string text = "Hello";

    cout << "Length = " << text.length();

    return 0;
}

Length = 5

String Example 5: Join Two Strings String Example 5: दो Strings को जोड़ना

#include <iostream>
using namespace std;

int main() {

    string firstName = "Rahul";
    string lastName = "Sharma";

    string fullName = firstName + " " + lastName;

    cout << "Full Name = " << fullName;

    return 0;
}

Full Name = Rahul Sharma

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