C++ Examples

🧪 C++ Examples – Learn by Doing!

The best way to learn C++ is by writing and running code. Below are a bunch of simple, real-life examples to help you understand how things work in the C++ world. 🎯

🔢 Example: Add Two Numbers

#include <iostream>
using namespace std;

int main() {
    int a = 5, b = 10;
    int sum = a + b;

    cout << "Sum: " << sum << endl;
    return 0;
}

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📐 Example: Area of a Rectangle

#include <iostream>
using namespace std;

int main() {
    int length = 8, width = 4;
    int area = length * width;

    cout << "Area: " << area << endl;
    return 0;
}

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📊 Example: Check Even or Odd

#include <iostream>
using namespace std;

int main() {
    int number = 7;

    if (number % 2 == 0)
        cout << number << " is even." << endl;
    else
        cout << number << " is odd." << endl;

    return 0;
}

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⏱️ Example: Simple Loop

#include <iostream>
using namespace std;

int main() {
    for (int i = 1; i <= 5; i++) {
        cout << "Count: " << i << endl;
    }
    return 0;
}

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🌟 Example: Star Triangle

#include <iostream>
using namespace std;

int main() {
    int rows = 5;

    for (int i = 1; i <= rows; i++) {
        for (int j = 1; j <= i; j++) {
            cout << "* ";
        }
        cout << endl;
    }
    return 0;
}

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⬛ Example: Print Square Pattern

#include <iostream>
using namespace std;

int main() {
    int size = 4;

    for (int i = 1; i <= size; i++) {
        for (int j = 1; j <= size; j++) {
            cout << "* ";
        }
        cout << endl;
    }
    return 0;
}

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🔢 Example: Fibonacci Series

#include <iostream>
using namespace std;

int main() {
    int n = 10;
    int t1 = 0, t2 = 1, nextTerm;

    cout << "Fibonacci Series: " << t1 << ", " << t2;

    for (int i = 3; i <= n; ++i) {
        nextTerm = t1 + t2;
        cout << ", " << nextTerm;
        t1 = t2;
        t2 = nextTerm;
    }

    cout << endl;
    return 0;
}

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🎯 Example: Number Guessing Game

#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;

int main() {
    srand(time(0)); // Random seed
    int secret = rand() % 10 + 1;
    int guess;

    cout << "Guess a number between 1 and 10: ";
    cin >> guess;

    if (guess == secret) {
        cout << "🎉 Wow! You guessed it right!";
    } else {
        cout << "Oops! The number was " << secret << ". Try again!";
    }

    return 0;
}

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🔄 Example: Swap Two Numbers Without Temp

#include <iostream>
using namespace std;

int main() {
    int a = 5, b = 10;

    cout << "Before Swap: a = " << a << ", b = " << b << endl;

    a = a + b;
    b = a - b;
    a = a - b;

    cout << "After Swap: a = " << a << ", b = " << b << endl;
    return 0;
}

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Code Output

Before Swap: a = 5, b = 10
After Swap: a = 10, b = 5

Explanation

  • a = a + b; → a = 15

  • b = a - b; → b = 15 - 10 = 5 (b gets the original value of a)

  • a = a - b; → a = 15 - 5 = 10 (a gets the original value of b)

 

🔁 Example: Reverse a Number

#include <iostream>
using namespace std;

int main() {
    int num = 12345, rev = 0;

    while (num != 0) {
        rev = rev * 10 + num % 10;
        num /= 10;
    }

    cout << "Reversed Number = " << rev << endl;
    return 0;
}

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🧮 Example: Simple Calculator

#include <iostream>
using namespace std;

int main() {
    char op;
    float a, b;

    cout << "Enter operator (+, -, *, /): ";
    cin >> op;

    cout << "Enter two numbers: ";
    cin >> a >> b;

    switch(op) {
        case '+': cout << "Result: " << a + b; break;
        case '-': cout << "Result: " << a - b; break;
        case '*': cout << "Result: " << a * b; break;
        case '/': 
            if (b != 0)
                cout << "Result: " << a / b; 
            else 
                cout << "Division by zero not allowed!";
            break;
        default: cout << "Invalid operator!";
    }

    return 0;
}

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🧠 Tip:

Try changing the values in each program and run them again! Playing with the code is the best way to remember it. 💡