Vector and class copy constructors

// vec_d.cpp :  This file contains  "main"  function . Program execution will start and end here .
//

#include <iostream>
#include <vector>

class test
{
public:
	double *a;
	test() { a = nullptr; };
	test(int size) {
		a = new double[size];
		for (int i=0;i<size;i++)
		{
			a[i] = i;
		}
	};
};

class test1
{
public:
	
	test1() {};
	test1(double val) {
		for (int i = 0; i < 10; i++)
		{
			a[i] = val;
		}
	};
private:
	double a[10];
};

using namespace std;

int main()
{
	vector<test1> vec_t;
	test1 new_t(10.0);
	vec_t.push_back(new_t);
}

vector The copy constructor is used when adding elements . The compiler generates a shallow copy of the copy constructor .

test1 This class uses a fixed length array , Shallow copy is OK .

test This class uses pointers , Realize dynamic length array . You need to use a deep copy constructor .

Why can the default copy constructor handle correctly test1 This kind of copy ？ It shows that its implementation is to directly copy the values in memory . The value of the pointer is the memory address of the dynamic array . therefore , It is wrong to copy the value of the pointer .