#include <iostream>#include <thread>int counter = 0;void increment() { for (int i = 0; i < 100000; ++i) { // ++counter实际上3条指令 // 1. int tmp = counter; // 2. tmp = tmp + 1; // 3. counter = tmp; ++counter; }}int main() { std::thread t1(increment); std::thread t2(increment); t1.join(); t2.join(); std::cout << "Counter = " << counter << "\n"; return 0;}