A student's question

My teacher keeps drilling into our collective heads that using the break command is harmful, and that if we wish to terminate a loop early it would be far better to create a boolean variable, set it to 0, and add a condition to the head of the loop, and set the boolean variable to 1 when a break is needed. Note that this way you actually have to check this every single loop (where it is not needed almost every time) as well as waste a command to reset the boolean in case it was set to true.

Is there a reason to this?

It's about source code clarity. Ensuring loops and functions have only one entry point and only one exit point keeps control flow simple and lessens the risk of introducing bugs when modifying the code.

It's the kind of rule that you're likely to see in large projects where it's expected someone else will have to do maintenance on your code years after you've left the company.