Answer 1

"Can you expalain me about operator"

Some notations specified by a particular language to perform/help to perform some meaningful operations like arithmetic operations. Operators in C++ grouped in some categories. For example:

Arithmetic operators: https://en.cppreference.com/w/cpp/language/operator_arithmetic

Comparison operators: https://en.cppreference.com/w/cpp/language/operator_comparison

Increment/decrement operators: https://en.cppreference.com/w/cpp/language/operator_incdec

etc.

Also a comprehensive explanation is available here: https://en.wikipedia.org/wiki/Operators_in_C_and_C%2B%2B