[c++] Implicit type conversion rules in C++ operators

The type of the expression, when not both parts are of the same type, will be converted to the biggest of both. The problem here is to understand which one is bigger than the other (it does not have anything to do with size in bytes).

In expressions in which a real number and an integer number are involved, the integer will be promoted to real number. For example, in int + float, the type of the expression is float.

The other difference are related to the capability of the type. For example, an expression involving an int and a long int will result of type long int.