Chapter 26 // Exercise 5 - Principles & Practice Using C++

In this exercise I'm using Visual Studio 2019 and a modified version of the std_lib_facilities header found here.

Chapter 26 // Exercise 5

Add a test to the set of binary_search tests to try and catch the (unlikely) error of a binary_search modifying the sequence.

Github: https://github.com/l-paz91/principles-practice/blob/master/Chapter%2026/Exercise%205

I was a bit confused by this as std::binary_search does not modify anything passed to it. The sequence must already be sorted (or it won't work properly). I tried googling for this and couldn't find any information on it. I then asked ChatGPT-4 and it said std::binary_search will not modify but could provide undefined behaviour if the sequence wasn't sorted.

I then thought that maybe, the predicate function you can pass to binary_search would be able to modify the sequence in some way however the variables are passed to the predicate by const so you would have to const_cast to change them which is considered very bad.

I then told Chat this and gave it the name of the book, the author and the exercise and it pretty much told me "you're reading into this too much, you're supposed to just write a test that shows it doesn't modify the sequence". Should've added "duh" at the end as well.

Once again, taking things literally and overthinking was not the answer.

So instead in TestAll I made a local copy of the sequence then added an if that checks if the sequence has changed after the binary_search was done. No new test needed.