Functions that are `O(n)`

increase the number of operations linearly, as the input gets very large. A simple example of a function that is O(n) would be the linear search algorithm, which runs once for the size of the input.

The following pseudo-code would be `O(n)`

, because it will always be bounded above by the input size, as the algorithm will never run more times then the input size.

```
function LinearSearch (SearchArray, SearchFor)
for each element in SearchArray
if the element is SearchFor
return the index of element
```