Calculator Help (C++)

Question

Hey guys, I'm having trouble with a calculator I'm trying to code. (First ever project) it keeps returning huge values that just aren't right. I was wondering if someone could take a look and tell me what's wrong? https://code.sololearn.com/c69S7JfR48PO/#cpp

Answer 1

https://code.sololearn.com/ccwmPZ6KAUyC/?ref=app

Answer 2

https://code.sololearn.com/cRHZxCar3VOO/?ref=app

Answer 3

first input
then use value of a and b
you are using garbage value and then input in a,b