Is the size of C “int” 2 bytes or 4 bytes?

Question

Does an Integer variable in C occupy 2 bytes or 4 bytes? What are the factors that it depends on?

Most of the textbooks say integer variables occupy 2 bytes. But whe

Answer 1

Is the size of C “int” 2 bytes or 4 bytes?

The answer is "yes" / "no" / "maybe" / "maybe not".

The C programming language specifies the following: the smallest addressable unit, known by char and also called "byte", is exactly CHAR_BIT bits wide, where CHAR_BIT is at least 8.

So, one byte in C is not necessarily an octet, i.e. 8 bits. In the past one of the first platforms to run C code (and Unix) had 4-byte int - but in total int had 36 bits, because CHAR_BIT was 9!

int is supposed to be the natural integer size for the platform that has range of at least -32767 ... 32767. You can get the size of int in the platform bytes with sizeof(int); when you multiply this value by CHAR_BIT you will know how wide it is in bits.

---

While 36-bit machines are mostly dead, there are still platforms with non-8-bit bytes. Just yesterday there was a question about a Texas Instruments MCU with 16-bit bytes, that has a C99, C11-compliant compiler.

On TMS320C28x it seems that char, short and int are all 16 bits wide, and hence one byte. long int is 2 bytes and long long int is 4 bytes. The beauty of C is that one can still write an efficient program for a platform like this, and even do it in a portable manner!