C++ 析构函数调用 Class 指针调用另一个 class

Question

I am working on a school project where I have to parse information from a string array and then place them into an object (class1) of one class using an array of pointers called in another class (class2). I am able to get the information into the class1 object but when I try to remove a single class1 object using the pointer in class 2 either nothing happens, I can empty an array stored in class1 object, or I receive scope errors (cannot delete expression of type class1), depending on how I manipulate my code. Here is a small sample:

 class Class1 {
 public:
  //Declare constructors
  Class1 (int num, string word, int array[]);
  Class1 ();

  //Destructor
  ~Class1();
  };

   Class1::~Class1(){}
    //followed by definitions assigning variables using this->num = num; etc...

    //Declare Class2
   class Class2 {
   public:
   int index = 0;
   int numStudent;
   //Constructors
   Class2(numStudent);
   Class2();

   ~Class2();
 
   Class1* arrayPtr[5];
   };
   
     //Class2 Definitions
     Class2::Class2 (int numStudent) {
      this->numStudent = numStudent;
      for (int i = 0; i < numStudent; ++i) {
       arrayPtr[i] = new Class1;
     }
     }

     Class1::Class1(){}
     //
     Class2::~Class2() {
        delete[] arrayPtr;
     }

This way I receive an error on Class2 destructor to "Cannot delete expression of type 'Class1 *[3]'. I tried using delete arrrayPtr[I] in a for loop and received no error, outputted message saying Object Removed but recalling print still printed the Object that was supposed to be removed. Any explanation or tips would be helpful.

Answer 1

Mistake 1

The error means that you're trying to use delete[] on arrayPtr which is an array of size 3 with elements of type Class* . In other words, the operand for the delete[] in your example is an array and not a pointer. That is, the operand to delete or delete [] should be a pointer.

Mistake 2

Secondly, nowhere in your program you've used new[] form so using delete[] is incorrect. That is, since you've used new form, you should be using the delete form instead of delete[] .

The correct way to do this would be to loop through the array using a say for loop and then using delete form on each element.

---

Note also that better would be to either use smart pointers or better yet use std::vector so that you don't have to do explicit memory management using new and delete .