How do you avoid copying an object in C++?

There are three ways to prevent such an object copy: keeping the copy constructor and assignment operator private, using a special non-copyable mixin, or deleting those special member functions. A class that represents a wrapper stream of a file should not have its instance copied around.

Does returning an object copy it C++?

Returning an object invokes the copy constructor while returning a reference doesn’t. So, the version #2 does less work and is more efficient. The reference should be to an object that exists when the calling function is execution.

What is * this pointer in C++?

The this pointer is an implicit parameter to all member functions. Therefore, inside a member function, this may be used to refer to the invoking object. Friend functions do not have a this pointer, because friends are not members of a class. Only member functions have a this pointer.

How do you make a non-copyable object?

The typical way to make a C++ object non-copyable is to explicitly declare a copy constructor and copy-assignment operator but not implement them. This will prevent the compiler from generating its own.

How do you prevent an object from creation in C++?

You can prevent an object being declared with automatic duration (“on the stack”) by making its constructor private and providing a factory (abstract factory or factory method) to control creation of new objects.

How do you return a vector object in C++?

Return a Vector From a Function in C++

1. Use the vector func() Notation to Return Vector From a Function.
2. Use the vector &func() Notation to Return Vector From a Function.

Does returning a vector create a copy?

It get copied when return. No one guarantees.. It will die, but after it’s copied.

How do I return from a class in C++?

You either need to return by value, or return an Object declared in a wider scope or new ed onto the heap. Object& return_Object(); if the object returned has a greater scope than the function. For example, you can use it if you have a class where it is encapsulated.

How do I return a temporary object in C++?

You are returning a temporary object, but because you return it by value, the copy is created. If you return pointer or reference to temporary object, that would be a mistake. If you change the return type to const char * and return ss. str().