What is the error?

#1

Not able to pass test cases. Whats the error?
link to my code - https://ide.codingblocks.com/s/221545

#2

Which testcase is failing??

#3

all test cases are failing.

#4

check the return type of power function. It should be long long int

#5

code is still not working.

#6

Try to submit this: