error for using string in writing a library

Hi,
a few days ago I wrote a library that I use #include & #include in it, it was ok till I copy .cpp and .h files to arduinio>>library >>… file
when I add my library to Arduino IDE for using in my code there was a error and its error refers to #include & #include
now, if I want to use string or vector in my library’s code what should I do
thanks

if I want to use string or vector in my library’s code what should I do

You’re gonna need a bigger boat.

Youre going to need a bigger boat.jpg

now, if I want to use string or vector in my library's code what should I do

Re-think your approach. Consider how much memory you have, before you make any decisions.