-.-嘻嘻

#include using namespace std;template class Singleton{public: int get_data(); static Singleton* &get_ptr();public: int m_data; static Singleton *m_ptr;private: Singleton(){ m_data = 10;

#include using namespace std;class TestClass{ friend ostream& operator<<(ostream&, TestClass&);public: TestClass(int *ptr) :p(ptr){} TestClass(const TestClass &value) : p(new int(*(value.p)))

#include using namespace std;int main(){ //int *p = nullptr; ////const int *ptr = p; // OK ////const int* &pptr = p; // error: 无法用 "int *" 类型的值初始化 "const int *&" 类型的引用(非常量限定) ////int *const pt

#include <iostream>#include <thread>int main(){ for (int i = 0; i < 1; ++i) { std::thread([]() { std::cout << "thread" << std::endl; }).detach(); } f