C++: Closures/Value Capture

Task: Create a list of 10 functions, in the simplest manner possible (anonymous functions are encouraged), such that the function at index $i$ (you may choose to start $i$ from either 0 or 1), when run, should return the square of the index, that is, $i 2$ . Display the result of running any but the last function, to demonstrate that the function indeed remembers its value.

Goal: To demonstrate how to create a series of independent closures based on the same template but maintain separate copies of the variable closed over. In imperative languages, one would generally use a loop with a mutable counter variable. For each function to maintain the correct number, it has to capture the value of the variable at the time it was created, rather than just a reference to the variable, which would have a different value by the time the function was run.

#include <iostream>
#include <functional>
#include <vector>

int main() {
	std::vector<std::function<int()> > funcs;
	for (int i = 0; i < 10; i++)
	funcs.push_back([=]() { return i * i; });
	for ( std::function<int( )> f : funcs ) 
	std::cout << f( ) << std::endl ; 
	return 0;
}