std::move example

Here is an example of move semantics:

	#include <string>
	#include <vector>
	#include <utility>
	#include <iostream>
	const int STR_SIZE = 10000000;
	const int VEC_SIZE = 200000000;
	int main()
	{
	std::vector<std::string> vec;
	std::string str;
	for (int i = 0; i < STR_SIZE; ++i)
	{
	str += 'a';
	}
	for (int i = 0; i < VEC_SIZE; ++i)
	{
	vec.push_back(str);
	}
	std::vector<std::string> vec1(vec);
	//std::vector<std::string> vec1(std::move(vec));
	std::cout << vec1.size() << std::endl;
	std::cout << vec.size() << std::endl;
	return 0;
	}

view raw c.cpp hosted with ❤ by GitHub

When line 24 is used:

nonbonding@castor-ub:~/dnonbonding/tmp/rvalue$ g++ -std=c++11 c.cpp && time ./a.out
200000000
200000000

real 0m31.475s
user 0m24.932s
sys 0m4.604s

When line 25 is used instead of line 24:

nonbonding@castor-ub:~/dnonbonding/tmp/rvalue$ g++ -std=c++11 c.cpp && time ./a.out 

200000000

0

real 0m17.334s

user 0m16.708s

sys 0m0.440s

Execution time was reduced by almost a half!