a user defined class of ARRAY in c++ with pointer - c++

Question

This code is a class of arrays definition that uses dynamic memory to allocate memory. The command ArrayClass temp(_size); in operator+ method gives the following runtime error.
Unhandled exception at 0x7715C54F in ArrayClass.exe: Microsoft C++
exception: std::bad_array_new_length at memory location 0x0033FB10.
If we convert this command to ArrayClass *temp = new ArrayClass(_size), no error will be occured. But the new object temp that was allocated by new operator will not be deleted.
Does anyone have a solution?
#include <iostream>
using namespace std;
class ArrayClass {
private:
int _size;
float* _ar;
public:
ArrayClass(const int& size) {
_size = size;
_ar = new float[_size];
}
~ArrayClass() {
delete[]_ar;
}
const ArrayClass& operator=(const ArrayClass& RightOperand) {
if (this != &RightOperand) {
if (this->_size != RightOperand._size) {
delete[] this->_ar;
this->_size = RightOperand._size;
this->_ar = new float[this->_size];
}
for (int i = 0; i < RightOperand._size; i++)
{
this->_ar[i] = RightOperand._ar[i];
}
}
return *this;
}
const ArrayClass& operator+(const ArrayClass& RightOperand) {
//*this+RightOperand
if (this->_size != RightOperand._size) {
cout << "different Size";
exit(1);
}
ArrayClass temp(_size);
for (int i = 0; i < _size; i++)
{
temp._ar[i] = this->_ar[i] + RightOperand._ar[i];
}
return temp;
}
};
int main() {
ArrayClass x(5), y(5), z(5);
x = y;
z= x + y;
return 0;
}