How Data type sizes differ for C or C++ languages based on 32 bit and 64 bit systems

Question

I have few basic questions regarding the size of data types for C and C++ languages on 32 bit and 64 bit systems. I have failed to get a convincing answer on net for the same, and my questions are.

• Say for C++ language, does the data type size depends on,
  • Whether the compiler is 32 bit or 64 bit
  • Whether the computer architecture is 32 bit or 64 bit
  • Or, C++ language standards for 32 bit and 64 bit systems.

Thanks in advance.

Regards, Vijay.

Answer 1

They practically depend on everything, maybe even on compiler flags, so don't make assumptions. Either lool up the documentation of the platforms you target, or (in case of integers) use the fixed-width standard types (<stdint.h> in C, <cstdint> in C++).