[r.stiltskin]

Notice that here

        int yards, feet;

when you declared two variables of type int, you specified names for the two variables

but here

typedef struct
{
        yardsfeetincheslength;
        yardsfeetincheswidth;

} yardsfeetinches;

you declared a variable of type yardsfeetincheslength and a variable of type yardsfeetincheswidth, but didn't give a name for either.

Also, do d1, d2, etc, have members inches, feet, yards? (No -- they have struct members, and those struct members have the inches, etc.)

This post has been edited by r.stiltskin: 28 April 2010 - 07:48 PM

[jjl]

Quote

reate a structure within a structure

i dont see any structs with in structs anywhere

typedef struct a
{
      typedef struct b
      {  
      };
};

[taiku]

Does that even work?

[r.stiltskin]

Andy, on 28 April 2010 - 10:42 PM, said:

so I need to change them to?

typedef struct
{
	int yardsfeetincheslength;
	int yardsfeetincheswidth;

} yardsfeetinches;

No. The way you have it now, yardsfeetincheslength is a type, and yardsfeetincheswidth is a type. But I don't know why you want to have different types for length and width. Why not have a measurement type containing the yards, feet, inches and total variables? And a rectangle type that contains two measurement members, as in:

measurement length;
measurement width;

[jjl]

Quote

Does that even work?

why wouldn't it?

This post has been edited by ImaSexy: 28 April 2010 - 08:09 PM

[baavgai]

// good, you've defined a type
typedef struct {
	int yards, feet;
	float inches, total;
} yardsfeetincheslength;


// wait a minute, you're defining the exact same struct as a different type
typedef struct
{
        int yards, feet;
        float inches, total;

} yardsfeetincheswidth;

// you define a type, with a couple of other types inside
// however, what are their names?
typedef struct
{
        yardsfeetincheslength;
        yardsfeetincheswidth;

} yardsfeetinches;

First, consider typedefs:

struct YFIT {
	int yards, feet;
	float inches, total;
};

// now the typedefs
typedef struct YFIT yardsfeetincheswidth;
typedef struct YFIT yardsfeetinches;

Imagine the compiler takes the "struct YFIT" and replaces it with "struct { int yards, feet; float inches, total; };" in the typedef, which is essentially what's happening.

Howevever, I don't believe you want this. I believe, you want this:

typedef struct {
	struct { 
		int yards, feet; 
		float inches, total; 
	} yardsfeetincheslength, yardsfeetincheswidth;
} yardsfeetinches;

Or, to avoid that anonymous struct:

typedef struct { 
	int yards, feet; 
	float inches, total; 
} yardsfeetinchestotal;

typedef struct {
	yardsfeetinchestotal yardsfeetincheslength;
	yardsfeetinchestotal yardsfeetincheswidth;
} yardsfeetinches;

Hope this helps.

ImaSexy, on 28 April 2010 - 09:08 PM, said:

why wouldn't it?

A few reasons, actually. First, typedef is basically an alias to some other definition, even an anonymous one. So, the first fail is:

typedef struct a { /* .. */ };  // <-- and the name of the typedef is ????.

Now, while a struct in struct is fine. a typedef in a struct in not. This would work:

typedef struct a {
	int x;
	struct { int y; } b;
} a;

[r.stiltskin]

baavgai, on 29 April 2010 - 08:55 AM, said:

[quote name='ImaSexy' date='28 April 2010 - 09:08 PM' timestamp='1272510532' post='1004136']
why wouldn't it?
[/quote]

A few reasons, actually.  First, typedef is basically an alias to some other definition, even an anonymous one.  So, the first fail is:
[code]
typedef struct a { /* .. */ };  // <-- and the name of the typedef is ????.

Now, while a struct in struct is fine. a typedef in a struct in not.

Really?

What's wrong with this:

#include <stdio.h>

typedef struct {
  int minutes, hours, days;
  double seconds;
} Clock;

typedef struct {
  Clock c1, c2;
} Timer;

int main() {
  printf("size of Timer: %d\n", sizeof(Timer));
  Timer timer;
  timer.c1.minutes = 5;
  timer.c1.hours = 2;
  timer.c1.days = 3;
  timer.c1.seconds = 44.5;
  printf("total elapsed time is %f seconds\n",
    timer.c1.seconds + 60*timer.c1.minutes + 3600*timer.c1.hours
       + 86400*timer.c1.days);
  return 0;
}

[baavgai]

r.stiltskin, on 29 April 2010 - 07:26 AM, said:

baavgai, on 29 April 2010 - 08:55 AM, said:

Now, while a struct in struct is fine. a typedef in a struct in not.

Really?

What's wrong with this:

#include <stdio.h>

typedef struct {
  int minutes, hours, days;
  double seconds;
} Clock;

typedef struct {
  Clock c1, c2;
} Timer;

I don't see the word "typedef" inside the block for struct. So what's wrong is that this has little to do with what you're quoting.

To reiterate, this is fine:

typedef struct {
	struct Clock {
		int minutes, hours, days;
		double seconds;
	} c1, c2;
} Timer;

This is not:

typedef struct {
	typedef struct {
		int minutes, hours, days;
		double seconds;
	} Clock;
	Clock c1, c2;
} Timer;

Also, this is not:

typedef struct {
	struct {
		int minutes, hours, days;
		double seconds;
	} Clock;
	Clock c1, c2;
} Timer;

To be clear, defining a named type inside a struct is illegal in C. You may define anonymous types and, of course, you may reference predefined types. This differs from C++, where you can define a type in a type.

[r.stiltskin]

OK, sorry, I assumed (who knows why) that we were talking about the OP's question, which has to do with instantiating a struct within a struct, not defining or typedef'ing a struct inside another struct.

[baavgai]

I assumed I was responding to the quote I had referenced.

Still, good for clarification. If one person is confused, others are likely confused as well.

[PsychoCoder]

Andy: Topics merged, there was no need to open a 2nd thread