One important new feature of C++11 was lambda expressions. In C++14 and C++17, the lambda expressions got some new additions, which have made them even more powerful. But first, what is a lambda expression?
Lambda expressions or lambda functions construct closures. A closure is a very generic term for unnamed objects that can be called like functions. In order to provide such a capability in C++, such an object must implement the () function calling operator, with or without parameters. Constructing such an object without lambda expressions before C++11 could still look like the following:
#include <iostream>
#include <string>
int main() {
struct name_greeter {
std::string name;
void operator()() {
std::cout << "Hello, " << name << '\n';
}
};
name_greeter greet_john_doe {"John Doe"};
greet_john_doe();
}Instances of the name_greeter struct obviously carry a string with them. Note that both this...