Question

Recently, I am confused with this two expression – (type)value and type(value).

For example : size_t c = size_t(-1); size_t c = (size_t)-1;

what is the difference?

Answer 1

The former is C++, it’s doing direct initialization by calling a constructor.

The second is C (or C++), it’s doing a cast.

So, there’s a lot of difference from a C programmer’s point of view.

Also, this is a pretty bad idea, since size_t is an unsigned type. This should be done using ssize_t, which is signed and removes the need for the cast.