\( \begin{array}{l}\text { What happens when you define a class that used } \\ \text { dynamic memory allocation and define a destructor } \\ \text { but no copy constructor? } \\ \text { It is possible to modify the values in the argument in the } \\ \text { function. } \\ \begin{array}{l}\text { When an object that was used as an argument for a call- } \\ \text { by-value parameter goes out of scope, it will cause a run- } \\ \text { time error. } \\ \text { If an object of the class is plugged in for a call-by-value } \\ \text { parameter, when the function ends, the parameter's } \\ \text { dynamic memory is returned to the freestore at the end } \\ \text { of the function execution. }\end{array} \\ \text { all of these } \\ \text { none of these }\end{array} \) vices

To analyze the situation described in the problem, let's break down the implications of defining a class with dynamic memory allocation, a destructor, but no copy constructor. 1. **Dynamic Memory Allocation**: When a class uses dynamic memory allocation (e.g., using `new`), it allocates memory on the heap. This memory must be explicitly released using `delete` to avoid memory leaks. 2. **Destructor**: A destructor is defined to clean up resources when an object goes out of scope. If the destructor is properly implemented, it will release the dynamically allocated memory. 3. **No Copy Constructor**: If a class does not define a copy constructor, the compiler provides a default one. The default copy constructor performs a shallow copy, meaning it copies the pointer to the dynamically allocated memory rather than the actual data. This can lead to issues when two objects point to the same memory location. 4. **Call-by-Value Parameter**: When an object is passed by value to a function, a copy of the object is made. If the class has a default copy constructor, the pointer to the dynamic memory will be copied, leading to two objects pointing to the same memory. 5. **Scope and Runtime Error**: When the function ends, the copy of the object (the parameter) goes out of scope, and its destructor is called. If the destructor deallocates the memory, the original object (outside the function) will now have a dangling pointer, leading to undefined behavior if it tries to access that memory later. 6. **Memory Management**: If the original object tries to deallocate the same memory when it goes out of scope, it will result in a double deletion, causing a runtime error. Now, let's evaluate the statements: - **"It is possible to modify the values in the argument in the function."**: This is true, as the function can modify the values of the object passed by value, but it won't affect the original object outside the function. - **"When an object that was used as an argument for a call-by-value parameter goes out of scope, it will cause a runtime error."**: This is true because of the shallow copy issue leading to potential double deletion or dangling pointers. - **"If an object of the class is plugged in for a call-by-value parameter, when the function ends, the parameter's dynamic memory is returned to the freestore at the end of the function execution."**: This is misleading. The memory is deallocated, but it can lead to issues if the original object tries to access that memory afterward. Given this analysis, the correct answer is: **All of these** - because all statements reflect the consequences of the described situation.