C++11: lockせずにデータ競合を防ぐ - Qiita

#include <iostream> #include <thread> using namespace std; int value = 0; void increment(int n) { for (int i = 0; i < n; ++i) { value = value + 1; } } void decrement(int n) { for (int i = 0; i < n; ++i) { value = value - 1; } } int main() { const int N = 100000; thread th0(&increment, N); thread th1(&decrement, N); th0.join(); th1.join(); cout << value << endl; // はたして0か!? } #include <iostream> #i