size guarantee for integral/arithmetic types in C and C++

Question

I know that the C++ standard explicitly guarantees the size of only char, signed char and unsigned char. Also it gives guarantees that

Answer 1

The C standard do not explicitly say that long has to be at least 4 bytes, but they do specify a minimum range for the different integral types, which implies a minimum size.

For example, the minimum range of an unsigned long is 0 to 4,294,967,295. You need at least 32 bits to represent every single number in that range. So yes, the standard guarantee (indirectly) that a long is at least 32 bits.

C++ inherits the data types from C, so you have to go look at the C standard. The C++ standard actually references to parts of the C standard in this case.