C++ Tutorial - Copy Constructors

If you have an array of objects, the only constructor that can be called on each object is the default constructor. You cannot use a non default constructor to construct arrays of objects. So if we reuse the phonerec declaration from the previous page:

phonerec() : name("Me"),phonenunber("555-1000") {}

phonerec subscribers[3];

The example below uses an initializer list that constructs each object in an array of 10 objects, and calls a function to set each object to have a different id value. After the array has been constructed, A[0]has an id of 0, A[1] an id of 1 etc.

#include <string>

using namespace std;

int x=0;
int getX() {
    return x++;
}

class a {
  public:

   int b;
    int id;
    string s;
    
    a() : id(getX()), b(5), s("value2") { }
    
};

void main() {
    a A[10];
}

a A[10];

On the next page Creating and Using Copy Constructors

• A Reminder about Constructors
• Using Initializer Lists
• Initializing an Array with a Default Constructor
• Initializing References
• Creating and Using Copy Constructors
• An Example of a Copy Constructor
• Using Assignment Operators
• An Example of Copy Constructors and Assignment Operators
• How Example One Works
• Summing up Constructors and Assignment Operators