passing an object

[jacek]

You can pass by value if copying is cheap (for example you want to pass an integer or char) or when you know that you have to make a copy anyway. Otherwise passing by reference is cheaper.

[mickey]

yes, but suppose to have a program larger than 100 000 lines of code where I could have many function that pass one char or int; if I did all by value (suppose even in those case by value or by reference has no difference) isn't it bad?

[jpn]

Passing a primitive data type (char, short, int, long, enum...) by value costs the same as passing it by reference.