如果在C++的块内创建对象，该对象存储在哪里？

可以将对象存储在内存的两个部分中：

1. 堆栈–堆栈中的内存供所有在块/功能内部声明的成员使用。注意main也是一个函数。
2. 堆–该内存未使用，可用于在运行时动态分配内存。

在块或函数内部创建的对象的范围仅限于在其中创建对象的块。

• 在功能块内部创建的对象将存储在堆栈中，并且当函数/ block退出时，对象将被销毁并从堆栈中删除。
• 但是，如果我们在运行时即通过动态内存分配创建对象，则该对象将存储在堆中。这是在新运算符的帮助下完成的。在这种情况下，我们需要使用delete运算符显式销毁对象。

例子：

Output:
Inside Block1...
length of rectangle is : 2
width  of rectangle  is :3
Destructor of rectangle
with the exit of the block, destructor called
automatically for the object stored in stack.
*********************************************
Inside Block2
length of rectangle is : 5
width of rectangle  is :6
Destructor of rectangle
length of rectangle is : 0
width of rectangle is :0

下面是显示对象存储位置的程序：

// C++ program for required implementation
#include 
using namespace std;
  
class Rectangle {
    int width;
    int length;
  
public:
    Rectangle()
    {
        length = 0;
        width = 0;
    }
  
    Rectangle(int l, int w)
    {
        length = l;
        width = w;
    }
  
    ~Rectangle()
    {
        cout << "Destructor of rectangle" << endl;
    }
  
    int getLength()
    {
        return length;
    }
  
    int getWidth()
    {
        return width;
    }
};
  
int main()
{
    // Object creation inside block
    {
  
        Rectangle r(2, 3); // r is stored on stack
        cout << "Inside Block1..." << endl;
        cout << "length of rectangle is : " 
             << r.getLength() << endl;
        cout << "width  of rectangle  is :" 
             << r.getWidth() << endl;
    }
  
    cout << " with the exit of the block, destructor\n"
         << " called automatically for the object stored in stack." 
         << endl;
  
         /* 
          // uncomment  this code and run once you will get
         // the compilation error because the object is not in scope
         cout<<"length of rectangle is : "<< r.getLength();
         cout<< "width of rectangle is :" << r.getWidth();
        */
           
  
    Rectangle* ptr2;
    {
        // object will be stored in heap  
        // and pointer variable since its local
        // to block will be stored in the stack
  
        Rectangle* ptr3 = new Rectangle(5, 6);
        ptr2 = ptr3;
        cout << "********************************************"
             << endl;
        cout << "Inside Block2" << endl;
        cout << "length of rectangle is : " 
             << ptr3->getLength() << endl;
        cout << "width of rectangle  is :" 
             << ptr3->getWidth() << endl;
  
        // comment below line of code and 
        // uncomment *important line* 
        // and then check the object will remain
        // alive outside the block.
  
        // explicitly destroy object stored on the heap
        delete ptr3; 
    }
  
    cout << "length of rectangle is : " 
         << ptr2->getLength() << endl;
  
    cout << "width of rectangle is :" 
         << ptr2->getWidth() << endl;
      
     // delete ptr2;   /* important line*/
  
    return 0;
}

输出：

Inside Block1...
length of rectangle is : 2
width  of rectangle  is :3
Destructor of rectangle
 with the exit of the block, destructor
 called automatically for the object stored in stack.
********************************************
Inside Block2
length of rectangle is : 5
width of rectangle  is :6
Destructor of rectangle
length of rectangle is : 0
width of rectangle is :0

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