Why the code inside if block not running?

Question

Input format:
int
+
int
And how to check variable type or data type?
https://code.sololearn.com/cKyKUYJsXXVA/?ref=app

Answer 1

Name

Use equals method instead of == because == compares reference not value.

if (sign.equals("+"))

https://code.sololearn.com/c3R6c3AdkvPl/?ref=app

Answer 2

ok got it... thanks