Try It Yourself - SyntaxStudy Editor

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#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>
#include <string>

int main() {
    // Basic lambda
    auto greet = [](const std::string& name) {
        std::cout << "Hello, " << name << "!
";
    };
    greet("Lambda");

// Capture by value
    int threshold = 5;
    auto isAbove = [threshold](int n) { return n > threshold; };
    std::cout << "6 above threshold: " << std::boolalpha << isAbove(6) << "
";

// Capture by reference — modifies outer variable
    int count = 0;
    auto increment = [&count]() { ++count; };
    increment(); increment(); increment();
    std::cout << "count = " << count << "
";  // 3

// Lambda in STL algorithm
    std::vector<int> nums = {3, 1, 4, 1, 5, 9, 2, 6};
    std::sort(nums.begin(), nums.end(),
              [](int a, int b) { return a > b; });  // descending
    for (int n : nums) std::cout << n << " ";
    std::cout << "
";

// std::function — type-erased callable
    std::vector<std::function<int(int)>> transforms;
    transforms.push_back([](int n) { return n * 2;  });
    transforms.push_back([](int n) { return n + 10; });
    transforms.push_back([](int n) { return n * n;  });

int val = 3;
    for (const auto& f : transforms)
        std::cout << "f(" << val << ") = " << f(val) << "
";

return 0;
}