structure initialization

[aarklon]

Hi all,

why the following structure initialization is not valid

#include<stdio.h>
struct rec
{
char name[10];
int age;
};
struct rec r;

int main(void)
{

r = {"Tom",32};
puts(r.name);

return 0;
}

 

[Vladimir S. Oka]

Hi all,

why the following structure initialization is not valid

Because the compiler does not know what type {"Tom",32} is.

#include<stdio.h>
struct rec
{
char name[10];
int age;
};
struct rec r;

int main(void)
{

r = {"Tom",32};

You could do:

r = (struct rec){"Tom",32};

Whether this is good style is another matter...

 

[Martin Ambuhl]

Hi all,

why the following structure initialization is not valid

It's not an initialization, but an assignment.

But this code, containing an initialization is OK:
#include <stdio.h>

struct rec
{
char name[10];
int age;
};

int main(void)
{
struct rec r = { "Tom", 32 };
puts(r.name);
return 0;
}


And with a C99 compiler, this code with an assignment is OK.

#include <stdio.h>

struct rec
{
char name[10];
int age;
};
struct rec r;

int main(void)
{
r = (struct rec) {"Tom", 32};
puts(r.name);

return 0;
}


[OP's code]

#include<stdio.h>
struct rec
{
char name[10];
int age;
};
struct rec r;

int main(void)
{

r = {"Tom",32};
puts(r.name);

return 0;
}

 

[Richard G. Riley]

"(e-mail address removed)"posted the following on 2006-03-09:

Hi all,

why the following structure initialization is not valid

#include<stdio.h>
struct rec
{
char name[10];
int age;
};
struct rec r;

int main(void)
{

r = {"Tom",32};
puts(r.name);

return 0;
}

Because it doesnt know that you are assigning a "struct rec" to r. It
needs to be explicitly told so that it can copy the right memory size
to your rec "r";

Change it so:

r = (struct rec){"Tom",32};

Or alternatively set the fields on their own using strcpy for name and
standard assignment for age. The direct assignment of the struct is
fast I think. If you are using gdb, step through and see how it works with

display/i $pc

and then

si

 

[white.crow]

this type of definition is static and according to Ritchie such
definitions sshould be done during declaration of the variable itself.

 

[Vladimir S. Oka]

this type of definition is static and according to Ritchie such
definitions sshould be done during declaration of the variable itself.

What type of definition? Ritchie? Guy Ritchie?

Quote what a nd who you're replying to or many people won't know what
you're talking about, and will ignore you. Read:
<http://cfaj.freeshell.org/google/>.

 

[Keith Thompson]

this type of definition is static and according to Ritchie such
definitions sshould be done during declaration of the variable itself.

What type of definition?

You should follow a newsgroup for a while, or browse the archives,
before posting. If you had done so here, you could have seen several
*hundred* references to <http://cfaj.freeshell.org/google/>, which
tells you how and why to provide sufficient context when posting
through groups.google.com.

Read <http://cfaj.freeshell.org/google/>. Read it now. Tell your
friends. And ask Google to fix their broken interface, so we can stop
having to remind poeple to read <http://cfaj.freeshell.org/google/>.

That's <http://cfaj.freeshell.org/google/>.