Why is is showing error in rotating the strings of larger length?
This is quite simple your for loop has condition which is never false for this input. So you are increasing i beyond size of s (double of size of s1).
Note common part of this two strings is: zqpquwjhuftohawpfegsjvnxwipwqlswvawogjuyiqtzsgpwgosegmuuhpzwchejuiitumyescxxyecnsatcbfpseqzowvdjyvchg.
Difference is:
-
s1has in front:ndafmffmuuwj -
s2has in backL:avqnonmkwgqp
So s1 is not rotation of s2 that is why codition in for is never fasle.
This is the reason std::basic_string::substr throws an exception.
Live demo.
Some fix.
And here is better way to do it.