[c++] Why is it OK to return a 'vector' from a function?

I think you are referring to the problem in C (and C++) that returning an array from a function isn't allowed (or at least won't work as expected) - this is because the array return will (if you write it in the simple form) return a pointer to the actual array on the stack, which is then promptly removed when the function returns.

But in this case, it works, because the std::vector is a class, and classes, like structs, can (and will) be copied to the callers context. [Actually, most compilers will optimise out this particular type of copy using something called "Return Value Optimisation", specifically introduced to avoid copying large objects when they are returned from a function, but that's an optimisation, and from a programmers perspective, it will behave as if the assignment constructor was called for the object]

As long as you don't return a pointer or a reference to something that is within the function returning, you are fine.

Examples related to c++

Method Call Chaining; returning a pointer vs a reference? How can I tell if an algorithm is efficient? Difference between opening a file in binary vs text How can compare-and-swap be used for a wait-free mutual exclusion for any shared data structure? Install Qt on Ubuntu #include errors detected in vscode Cannot open include file: 'stdio.h' - Visual Studio Community 2017 - C++ Error How to fix the error "Windows SDK version 8.1" was not found? Visual Studio 2017 errors on standard headers How do I check if a Key is pressed on C++

Examples related to vector

How to plot vectors in python using matplotlib How can I get the size of an std::vector as an int? Convert Mat to Array/Vector in OpenCV Are vectors passed to functions by value or by reference in C++ Why is it OK to return a 'vector' from a function? Append value to empty vector in R? How to initialize a vector with fixed length in R How to initialize a vector of vectors on a struct? numpy matrix vector multiplication Using atan2 to find angle between two vectors

Examples related to stl

Why is it OK to return a 'vector' from a function? How to remove all the occurrences of a char in c++ string How to use the priority queue STL for objects? use std::fill to populate vector with increasing numbers What does iterator->second mean? How to set initial size of std::vector? Sorting a vector in descending order How do I reverse a C++ vector? Recommended way to insert elements into map Replace an element into a specific position of a vector

Examples related to scope

Angular 2 - Using 'this' inside setTimeout Why Is `Export Default Const` invalid? How do I access previous promise results in a .then() chain? Problems with local variable scope. How to solve it? Why is it OK to return a 'vector' from a function? Uncaught TypeError: Cannot read property 'length' of undefined Setting dynamic scope variables in AngularJs - scope.<some_string> How to remove elements/nodes from angular.js array Limiting number of displayed results when using ngRepeat A variable modified inside a while loop is not remembered

Examples related to standard-library

Removing duplicate elements from an array in Swift Why is it OK to return a 'vector' from a function? How to check if a file exists in Go? "Unresolved inclusion" error with Eclipse CDT for C standard library headers Case Insensitive String comp in C Concatenating strings doesn't work as expected Read whole ASCII file into C++ std::string Getting a machine's external IP address with Python