So, I'm giving my phone number to a person so that they can count on me and call me if and when they have problems in the future.
Here are two sentences:
Here is my number in case you have problems.
Here is my number in case of problems.
Would you say that these two are correct and interchangeable?
Personally, I'm leaning more towards (1), but, perhaps, I'm overthinking.
Cambridge Dictionary brings out that there are two meanings of 'in case of [problems etc]':
in case of something:
if something happens, or in preparation for when something happens:
- The camping area has ready access to water, in case of fire.
- A doctor is on call in case of emergencies.
- In case of emergency, please contact the child's parent or guardian.
- In case of disagreement, an independent third party may be called upon.
- This provides increased protection in case of sickness or unemployment.
A more obvious example where the 'in preparation for when something happens' is forced is
And one where 'if something occurs' is forced is
Obviously, 'Here is my number in case of problems.' has the 'in case you [later] encounter problems' sense.
So either sentence works.
'Break the glass in case you [later] have a fire' wouldn't work.