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c++ 构建对象

admin 11月 13, 2020 0

1.第一种情况

#include <iostream>
using namespace std;
class Solution {
private:
	~Solution() {
		cout << "Destroy object" << endl;
	}
public:
	Solution() {
		cout << "Create object" << endl;
	}
	friend void destruct(Solution*);
};
void destruct(Solution* s) {
	delete s;
	cout << "destroy over" << endl;
}
int main() {
	Solution s;  //(1)
	Solution* s1 = new Solution; //(2)
	destruct(s1);
	return 0;
}

编译的结果: (1)构建对象出错， (2)正常
原因:
构建一个私有的构造函数，the compiler would generate a compiler error for non-dynamically allocated objects because compiler need to remove them from stack segment once they are not in use.

2.第二种情况

#include <iostream>
using namespace std;
class Solution {
private:
	void *operator new(size_t);
public:
	Solution() {
		cout << "Create object" << endl;
	}
	~Solution() {
		cout << "Destroy object" << endl;
	}
};
int main() {
	Solution s; //(1)
	Solution* s1 = new Solution; //(2)
	return 0;
}

编译的结果: (1)构建对象正常， (2)出错
原因：
重载了new, 并私有化