operator new【STL】

    知识点：    C++中的::operator new和::operator delete只负责分配空间，不负责构造与析构，与malloc和free功能差不多。

    测试：

    

 
#include <iostream>

using namespace std;

class A
{
public:
	A(){cout<<"default construction"<<endl;}
	A(int t_){cout<<"int construction"<<endl;}

	~A(){cout<<"destruction"<<endl;}
public :
	int t;
};

int main()
{
	cout<<"111"<<endl;
	A *ap = (A*)(::operator new( (1*sizeof(A) )));
	//ap->A(2);
	cout<<"222"<<endl;
	//destroy(ap);
	::operator delete(ap);
	cout<<"333"<<endl;

	return 0;
}