Question

I read that for user-defined types, postponing the defintion of a variable until a suitable initializer is available can lead to better performance.
why?

Answer 1

For user-defined types in particular, the constructor and setting method could me arbitrarily complex and time-consuming. Taking Steven’s example:

X x; // Calls X() 
x.Set(42); 

X x(42); // Calls X(int) 

… the implementation of X::X() and X::Set() might both be very time-consuming, and that’s why you read that the latter can have better performance.