struct within a struct?

[BigFish21]

For this program I have to write it seems I have to use a struct within a struct. I tried simply doing this:

typedef struct
{
  ...
  typedef struct
  {
    ...
    ...
  } S2;
} S1;

I get an error when trying that. What is the correct way to do this? Thanks

[brewbuck]

For this program I have to write it seems I have to use a struct within a struct. I tried simply doing this:

typedef struct
{
  ...
  typedef struct
  {
    ...
    ...
  } S2;
} S1;

I get an error when trying that. What is the correct way to do this? Thanks

Declare S2 before S1, not inside it. Then inside S1, create an instance of S2.

[vart]

struct S1
{
  ...
  struct S2
  {
    ...
    ...
  } s2;
} s1;

or

typedef struct
  {
    ...
    ...
  } S2;

typedef struct
{
  ...
  S2 s2;
} S1;

[dwks]

Short answer:

typedef struct
{
  ...
  struct  /* note: no typedef */
  {
    ...
    ...
  } S2;
} S1;

Sorry, I don't have time to explain this in much detail, but it boils down to typedefs defining a new type, while here you want to create part of another type. In short:

struct type {
    whatever contents;
} instance;
typedef struct type shortname;

shortname is just a new name for "struct type". When you put a structure in another structure, you want to declare an instance of the structure (instance) rather than use struct type or shortname.