true, false (and not TRUE, FALSE) exist in C++ as possible values of bool
type which is fundamental type (*built in* as char, int, e.t.c.).
From Bjarne Stroustrup's "The C++ programming language" Special Edition page
75:
This is what is guaranteed about sizes of fundamental types:
1=sizeof(char)<=sizeof(short)<=sizeof(int)<=sizeof(long)
1<=sizeof(bool)<=sizeof(long)
sizeof(char)<=sizeof(wchar_t)<=sizeof(long) (My note: wchar_t is *also*
fundamental type in C++)
sizeof(float)<=sizeof(double)<=sizeof(long double)
sizeof(N)=sizeof(signed N)=sizeof(unsigned N)
--- end of paste ---
When a bool type is converted to an integer type true is concerted to 1 and
false to 0. When an integer type is converted to bool, 0 is converted to
false and !=0 is converted to true.
E.g.:
bool x=true;
int y=x; // y==1
y=-10;
x=y; //x==true
x=0; //x==false
Ioannis
> -----Original Message-----
> From: dev...@li...
> [mailto:dev...@li...]On Behalf Of Alan Thomas
> Sent: Friday, January 05, 2001 2:07 PM
> To: dev...@li...
> Subject: [Dev-C++] thruth or consequences
>
>
> Are TRUE and FALSE provided somewhere as a standard definition
> in a C++ library or something? I have been defining them myself,
> but now I
> have problems with multiple definitions or something in header
> files. When
> I remove the multiple definitions, then TRUE and FALSE are no
> longer defined
> in "this scope."
> Thanks, Alan
>
>
>
> _______________________________________________
> Dev-cpp-users mailing list
> Dev...@li...
> http://lists.sourceforge.net/mailman/listinfo/dev-cpp-users
>
|
