How to initialise memory with new operator in C++?

by

It’s a surprisingly little-known feature of C++ (as evidenced by the fact that no-one has given this as an answer yet), but it actually has special syntax for value-initializing an array:

new int[10]();

Note that you must use the empty parentheses — you cannot, for example, use (0) or anything else (which is why this is only useful for value initialization).

This is explicitly permitted by ISO C++03 5.3.4[expr.new]/15, which says:

A new-expression that creates an object of type T initializes that object as follows:

…

  • If the new-initializer is of the form (), the item is value-initialized (8.5);

and does not restrict the types for which this is allowed, whereas the (expression-list) form is explicitly restricted by further rules in the same section such that it does not allow array types.

More Related Contents:

  1. Why should C++ programmers minimize use of ‘new’?
  2. What uses are there for “placement new”?
  3. Do the parentheses after the type name make a difference with new?
  4. In what cases do I use malloc and/or new?
  5. Is “delete this” allowed in C++?
  6. C++ new int[0] — will it allocate memory?
  7. Will new return NULL in any case?
  8. Is it possible to delete a non-new object?
  9. Call destructor and then constructor (resetting an object)
  10. new, delete ,malloc & free
  11. Avoid memory leaks in C++ Pointers [closed]
  12. C++ – destructors [closed]
  13. Initialization of all elements of an array to one default value in C++?
  14. delete vs delete[] [duplicate]
  15. How to get memory usage at runtime using C++?
  16. Is there a reason to call delete in C++ when a program is exiting anyway?
  17. initialize a const array in a class initializer in C++
  18. Why is stack memory size so limited?
  19. Why would one replace default new and delete operators?
  20. How do you determine the size of an object in C++?
  21. Initial capacity of vector in C++
  22. Implementing a std::vector like container without undefined behavior
  23. initialization: parenthesis vs. equals sign [duplicate]
  24. Memory allocation and deallocation across dll boundaries
  25. What’s the difference between parentheses and braces in c++ when constructing objects
  26. How to track memory allocations in C++ (especially new/delete)
  27. Initialization difference with or without curly braces in C++
  28. What is the order of evaluation in a member initializer list?
  29. C++ default initialization and value initialization: which is which, which is called when and how to reliably initialize a template-type member
  30. Should objects delete themselves in C++?

Leave a Comment