How do C/C++ compilers handle type casting between types with different value ranges?

Question

How do type casting happen without loss of data inside the compiler?

For example:

 int i = 10;
 UINT k = (UINT) k;

 float fl = 10.123;
 UINT  ufl =          


        

Answer 1

The two C-style casts in your example are different kinds of cast. In C++, you'd normally write them

unsigned int uf1 = static_cast(fl);

and

unsigned char* up = reinterpret_cast(p);

The first performs an arithmetic cast, which truncates the floating point number, so there is data loss.

The second makes no changes to data - it just instructs the compiler to treat the pointer as a different type. Care needs to be taken with this kind of cast: it can be very dangerous.