Cannot find the failed testcase

#1

i have tried to edit my code many times but still got 2 test cases failed. what am i doing wrong.
question: basic calculator
code:

#2

hey @zodiac, there is no need to print these xxx,XXX,lmao. And Invalid operation. Try again. should be same as given in question.
I have made changes on your code. Check them here https://ide.codingblocks.com/s/91058