Question

class table{
name *p; int i;
public:
table(int j=15){p=new name[i=j]} //constructor
~table(){delete[]p;}
}

 void h()     
{
    table t1;  
    table t2=t1; 
    table t3;  
    t3=t2;
}`

Bjarne wrote array created for t1 will be deleted 3 times as array created for t1 appears in t1,t2,t3**

Can you please explain what does this mean with some other examples.

Answer 1

If the copy constructor and operator = only copy the value of a pointer, in the end t1, t2 and t3 will have pointers to the same bit of memory. If table has a destructor that deletes the pointer, the same pointer will be deleted three times – once for every object. This should cause a segfault.

To prevent this a class can allocate a new array for every copy (called making a deep copy), or do reference counting.