size_t and auto

- [Instructor] Size_t is a basic unsigned integer.…It's size depends on the system.…It can store the maximum size…of a theoretically possible object of any type,…including a ray.…Using size_t can improve your code's…portability and efficiency.…Most index containers in the STL use size type,…which is another name for size_t.…Since C++14, you can use auto as a return type,…but all returns should have the same type.…

We have a code sample to illustrate the points.…So, let's switch over to Visual Studio Code.…And let's start off that we have…this function called, sumDown,…and it is a recursive add function.…You give it a number like 10,…and it'll keep going from 10 all the way down to zero,…and add all the numbers up along the way.…Now, notice that we have a type auto here…and we have a return type of zero for an integer.…And also, this is going to be an integer…of what's getting added here.…

And that's using auto as a return type.…Now here, we're using size_t in a various different ways.…We're going to create a constant N,…