d0thomas@dtek.chalmers.se (Thomas Lundqvist) (11/20/90)
Hello! Could someone please tell me the difference between:
struct TEST { int a; };
typedef struct { int a; } TEST
--
Thomas Lundqvist, d0thomas@dtek.chalmers.se
Chalmers Institute of Technology, Gothenburg, SWEDENgwyn@smoke.brl.mil (Doug Gwyn) (11/21/90)
In article <1990Nov20.153907.12373@mathrt0.math.chalmers.se> d0thomas@dtek.chalmers.se (Thomas Lundqvist) writes: >Hello! Could someone please tell me the difference between: >struct TEST { int a; }; >typedef struct { int a; } TEST The first declares a structure tag, the second (assuming you provide a terminating semicolon) declares a synonym for a tagless structure. K&R probably explains this.
schmidt@mars.jpl.nasa.gov (Kevin Schmidt) (11/21/90)
In article <1990Nov20.153907.12373@mathrt0.math.chalmers.se> d0thomas@dtek.chalmers.se (Thomas Lundqvist) writes: >Hello! Could someone please tell me the difference between: > >struct TEST { int a; }; > >typedef struct { int a; } TEST Both structures are identical but references to the structure as a type are different. For the first case to declare a variable of that type you would use: struct TEST x; In the second case you would simply use: TEST x; _______________________________________________________________________________ _ ____ _ | | / / / _ \ / / | Kevin T. Schmidt | schmidt@mars.jpl.nasa.gov / / / /_/ / / / | Jet Propulsion Laboratory | schmidt@jems.jpl.nasa.gov _ / / / ____/ / / | 4800 Oak Grove Dr. | / /_/ / / / / /___ | M/S 301-355 | \____/ /_/ /______/ | Pasadena, CA 91109 |
gordon@osiris.cso.uiuc.edu (John Gordon) (11/21/90)
d0thomas@dtek.chalmers.se (Thomas Lundqvist) writes: >Hello! Could someone please tell me the difference between: >struct TEST { int a; }; >typedef struct { int a; } TEST I think the difference is that if you use the first way, you will always have to say "struct TEST" whenever you declare a var of that type and the second way you can just say "TEST" without the "struct".
d0thomas@dtek.chalmers.se (Thomas Lundqvist) (11/21/90)
Well! Thank you all people who have replied my question (including those who have sent E-mail). I think I know the difference now. I will perhaps use the typedef form, because it's shorter. But the other form with a struct-tag is perhaps more informative because you have to write struct everywhere and then you wont have to investigate if its a struct or not... Bye, and thanks! Thomas Lundqvist, d0thomas@dtek.chalmers.se Chalmers Institute of Technology, Gothenburg, SWEDEN
prk@planet.bt.co.uk (KnightRider) (11/22/90)
d0thomas@dtek.chalmers.se (Thomas Lundqvist) writes: >Hello! Could someone please tell me the difference between: >struct TEST { int a; }; To use this later on, you have to use this code: struct TEST var1, *var2; >typedef struct { int a; } TEST To use this, you can do: TEST var1,*var2; >-- >Thomas Lundqvist, d0thomas@dtek.chalmers.se >Chalmers Institute of Technology, Gothenburg, SWEDEN Peter Knight BT Research #include <std.disclaimer>
mbrennan@swift.cs.tcd.ie (11/22/90)
In article <1990Nov20.153907.12373@mathrt0.math.chalmers.se>, d0thomas@dtek.chalmers.se (Thomas Lundqvist) writes: > Hello! Could someone please tell me the difference between: > > (1) struct TEST { int a; }; > > (2) typedef struct { int a; } TEST With case (1) you would delcare a variable: struct TEST foo ; but with case (2) you would write TEST foo ; In case (1) the words "struct TEST" together are a type, in the same way as int, char long etc are types, but with case (2) the word "TEST" on it's own is a type. -- , , , , , , , , , , Micheal O Braonain Roinn Riomheolaiochta, Colaiste Na Trinoide, BAC 2. Email mbrennan@cs.tcd.ie