Cpp2_7.html

<article>
    <h1>C++ II: Page 7 - Modern C++: Auto & Lambdas</h1>

    <section>
        <h2>Writing Cleaner, Faster Code</h2>
        <p>Modern C++ offers powerful features like <code>auto</code> for type deduction and <code>lambdas</code> for creating anonymous functions on-the-fly, making code significantly more expressive.</p>
        
        <h3>The Code implementation</h3>
        <pre><code class="language-cpp">/*
 * File: modern_cpp.cpp
 * Demonstration of auto type deduction, lambdas, and mutable lambdas
 */
#include &lt;iostream&gt;
#include &lt;vector&gt;
#include &lt;algorithm&gt;

using namespace std;

int main() {
    // 1. Auto type deduction
    auto x = 10;            // int
    auto y = 3.14;          // double
    auto z = "Hello";       // const char*
    
    // 2. Lambda expressions
    // [capture](params) -> return_type { body }
    auto add = [](int a, int b) -> int {
        return a + b;
    };
    
    cout << "Addition: " << add(5, 3) << endl;
    
    // 3. Capturing variables
    int multiplier = 10;
    auto multiply = [multiplier](int x) {
        return x * multiplier;
    };
    
    cout << "Multiplication: " << multiply(5) << endl;

    // 4. Mutable Lambda (modifying captured value)
    int count = 0;
    auto increment = [count]() mutable {
        return ++count;
    };
    
    cout << "Mutable lambda: " << increment() << endl;

    // 5. Using lambda in algorithm
    vector&lt;int&gt; nums = {1, 2, 3};
    for_each(nums.begin(), nums.end(), [](int n) {
        cout << n * 2 << " ";
    });
    
    return 0;
}

/*
 * Modern C++ Nuances:
 * 1. 'auto': Compiler deduces the type at compile-time, reducing verbosity.
 * 2. Lambdas: Great for quick, localized logic in algorithms.
 * 3. Capturing: [=] captures all by value, [&] captures all by reference.
 * 4. Lambdas are effectively function objects (functors) behind the scenes.
 * 5. Mutable lambdas ('mutable' keyword) allow modification of captured-by-value variables.
 * 6. Use 'auto' when the type is obvious, but prefer explicit types for API interfaces.
 */
        </code></pre>
        <div class="interactive-sim">
            <h3>Lambda Simulator</h3>
            <button class="sim-button" onclick="
                const out = document.getElementById('sim-output-cpp2_7');
                out.innerHTML = 'auto f = [](int x){ return x*2; };<br>';
                setTimeout(() => out.innerHTML += '>> f(5) is 10', 800);
            ">Run Simulation</button>
            <div id="sim-output-cpp2_7" class="sim-output"></div>
        </div>
    </section>
    <footer style="margin-top: 40px; padding: 20px; background: #f8f9fa; border-top: 1px solid #dee2e6;">
        <div style="display: flex; justify-content: space-between;">
            <a href="#" data-file="Cpp2_6.html" style="text-decoration: none; color: #6c757d;">&larr; Previous: Modern C++: Move Semantics</a>
            <a href="#" data-file="Cpp2_8.html" style="font-weight: bold; text-decoration: none; color: #007bff;">Next: Build: CMake &rarr;</a>
        </div>
    </footer>
</article>