In the C++ standard, the exact sizes of int and long are not fixed; instead, there is a requirement for a minimum range. This design aims to enhance portability of C++ across different platforms and systems.
For the int type, the C++ standard specifies that it must be able to represent at least a 16-bit integer. This means the size of int is at least 16 bits.
For the long type, the standard specifies that it must be able to represent at least a 32-bit integer, meaning the size of long is at least 32 bits.
It is important to note that these are minimum requirements. In specific implementations, the sizes of int and long may be larger, depending on the compiler and target platform architecture. For example, on many 64-bit systems, int is typically 32 bits, while long may be 64 bits.
Example:
Suppose we use the Microsoft Visual Studio compiler on a 32-bit Windows system; typically, int is 32 bits and long is also 32 bits. However, on a 64-bit Linux system using the GCC compiler, int remains 32 bits, but long may increase to 64 bits. This illustrates how the platform and compiler influence the sizes of these fundamental data types.