Lambda expression basics

Lambda expressions, or lambdas, were introduced in C++11. They are used to create an instance of an unnamed closure type in C++. A closure stores an unnamed function and can capture variables from its scope by value or reference. We can call operator () on a lambda instance, with arguments specified in the lambda definition, effectively calling the underlying unnamed function. To draw a parallel with C, lambdas are callable in the same way as function pointers.

We will now dive into an example to demonstrate how we can use lambdas in C++ and explain details regarding lambda capturing. Let us process the example below:

#include <cstdio>
#include <array>
#include <algorithm>
int main() {
    std::array<int, 4> arr{5, 3, 4, 1};
    const auto print_arr = [&arr](const char* message) {
        printf("%s\r\n", message);
        for(auto elem : arr) {
            printf("%d, ", elem);
        }
        printf...