Run-error in one test case in broken calculator problem

#1

I could not understand why the code is giving run-error in one test case.
link-https://ide.codingblocks.com/s/74372

#2

@rishu7865 hey rishabh increase the size from 500 to 1000 because test case may be large

#3

Sir how you got to know that test cases may be larger than 500 and also we are not taking input for test cases?

#4

@rishu7865 hey rishabh test case is not the only t. basically test case refer to input parameter which can check whether the program is working or not so basically In this question there are 7 to 8 test cases are designed for different sets of inputs
now come with why we choose value greater than 500 because every time developer team changes the test cases and may be they forgot to update the constraints size associate with problem