Joel Joel - 17 days ago 4
C++ Question

What is the difference between an int and a long in C++?

Correct me if I am wrong,

int is 4 bytes, with a range of values from -2,147,483,648 to 2,147,483,647 (2^31)

long is 4 bytes, with a range of values from -2,147,483,648 to 2,147,483,647 (2^31)

What is the difference in C++? Can they be used interchangeably?

Answer

It is implementation dependent.

For example, under Windows they are the same, but for example on Alpha systems a long was 64 bits whereas an int was 32 bits. This article covers the rules for the Intel C++ compiler on variable platforms. To summarize:

  OS           arch           size
Windows       IA-32        4 bytes
Windows       Intel 64     4 bytes
Windows       IA-64        4 bytes
Linux         IA-32        4 bytes
Linux         Intel 64     8 bytes
Linux         IA-64        8 bytes
Mac OS X      IA-32        4 bytes
Mac OS X      Intel 64     8 bytes  
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