Very basic question.. how do I write a short literal in C++?
I know the following:
2 is an int2L is a long2LL is a long long2.0f is a float2.0 is a double'\2' is a char.But how would I write a short literal? I tried 2S but that gives a compiler warning.
As far as I know, you don't, there's no such suffix. Most compilers will warn if an integer literal is too large to fit in whatever variable you're trying to store it in, though.
((short)2)
Yeah, it's not stricly a short literal, more of a casted-int, but the behaviour is the same and I there isn't a direct way of doing it.
That's what I've been doing because I couldn't find anything about it. I would guess that the compiler would be smart enough to compile this as if it's a short literal (i.e. it wouldn't actually allocate an int and then cast it every time).
The following illustrates how much you should worry about this:
a = 2L;
b = 2.0;
c = (short)2;
d = '\2';
Compile -> disassemble ->
movl $2, _a
movl $2, _b
movl $2, _c
movl $2, _d
I did some searching on google and found a good reference here
From that site an unsigned short can be done by L'ab' One or two characters in single quotes ('), preceded by the letter L
You don't, you just write a regular int literal and write it short enough to fit into a short. Or if your c++ doesn't have wchar_t as a native type, you could try L'xx' but thats kinda hacky.
Even the writers of the C99 standard got caught out by this. This is a snippet from Danny Smith's public domain stdint.h implementation:
/* 7.18.4.1 Macros for minimum-width integer constants
Accoding to Douglas Gwyn <[email protected]>:
"This spec was changed in ISO/IEC 9899:1999 TC1; in ISO/IEC
9899:1999 as initially published, the expansion was required
to be an integer constant of precisely matching type, which
is impossible to accomplish for the shorter types on most
platforms, because C99 provides no standard way to designate
an integer constant with width less than that of type int.
TC1 changed this to require just an integer constant
*expression* with *promoted* type."
*/