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What I am trying to do is create an array of structs, and initialize it through a function however I am getting a few errors,

lab2.c:20:2: error: declaration of anonymous struct must be a definition struct *person users[] = userInput(); ^ lab2.c:20:2: warning: declaration does not declare anything[-Wmissing-declarations] struct *person users[] = userInput(); ^~~~~~ lab2.c:24:1: error: declaration of anonymous struct must be a definition struct * userInput() { ^ lab2.c:48:2: error: expected identifier or '(' } ^ 1 warning and 3 errors generated.

Below is my code, in condensed version, if more is needed let me know, I'm pretty new to C so I'm guessing this is an obvious mistake on my part.

int main() { struct person users = userInput(); return 0; } struct * userInput() { struct person users[30]; ...do stuff to struct here... return *users; }
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  • users is a struct. userInput returns a struct*. Commented Oct 1, 2013 at 2:30
  • 1
    Your return type isn't valid. A struct* isn't a data type. Commented Oct 1, 2013 at 2:30

2 Answers 2

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When declaring a pointer to a tagged struct, the asterisk follows the tag, not the keyword struct. To declare a dynamically allocated array, use an asterisk without square brackets:

struct person *users = userInput();

Returning a pointer to a local variable is undefined behavior:

struct person users[30]; // This is wrong return *users;

Use dynamically allocated memory instead:

struct person *users = malloc(sizeof(struct user) * 30);

You will need to free it in the caller after you are done with the data.

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OK, there are a number of things wrong with your code. Ignoring the syntactical stuff when you do something like:

struct person users[30]

That memory is temporary and freed when the function returns. Most likely to give you an segmentation fault or corrupt data. You need something like:

#include <stdlib.h> typedef struct { char name[30]; int age; char gender; } person; person* userInput(); int main() { person* users = userInput(); return 0; } person* userInput() { person* users = malloc( 30 * sizeof(person) ); /* Init stuff here */ return users; }
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