catch(string& name) vs catch(string name)

Question

i.ex.: i throw exception
try{
throw int(123);}
catch(int& obj) {cout<<"With &: "<<obj;}
What is the difference betwen those two catch statments (what is the effect of using reference here?)
catch(int obj) {cout<<"Without: "<<obj;}
Both versions Of catch prints same output.

Answer 1

In this case, there is no reason to catch int(123) by reference other than C++ coding conventions.
The original reason to why people usually catch by reference involves the thrown exceptions inheriting from a base exception class.
https://stackoverflow.com/questions/2522299/c-catch-blocks-catch-exception-by-value-or-reference

Answer 2

<redacted>
Дмитрий Кузьмин (xeoneon), просьба ознакомиться с данным руководством:
https://www.sololearn.com/discuss/1183249/?ref=app