public/subjects/listsizeprog.en.md

## listsizeprog

## **WARNING! VERY IMPORTANT!**

For this exercise a function will be tested **with the exam own main**. However the student **still needs** to submit a structured program:

This means that:

- The package needs to be named `package main`.
- The submitted code needs one declared function main(```func main()```) even if empty.
- The function main declared needs to **also pass** the `Restrictions Checker`(illegal functions tester). It is advised for the student to just empty the function main after its own testings are done.
- Every other rules are obviously the same than for a `program`.

### Instructions

Write a function `ListSize` that returns the number of elements in a linked list `l`.

### Expected function and structure

```go
type NodeL struct {
	Data interface{}
	Next *NodeL
}

type List struct {
	Head *NodeL
	Tail *NodeL
}

func ListSize(l *List) int {

}
```