returning struct

[troye]

I have a function that is to return an entire struct. How would I declare the function? What do I use instead of the "void"?

Ex.

void get_data(void)
{
struct emp boss;
printf("Enter Employer's Name, Salary: "
scanf("%s %f", &boss.empname, &boss.salary);
get_date();
hired.yy = boss.hired.yy;
hired.mm = boss.hired.mm;
hired.dd = boss.hired.dd;

return boss;
}

 

[dsanchez2]

You need to define your function as:

struct emp get_date(void)

 

[Cagliostro]

If working in C++ mode you can do like this:

emp get_data(void)
...

Ion Filipski

 

[woja]

If working in C++ then it makes better sense to do this:

   void get_date(emp& value) {
      // ... do the stuff you need
      return;
   }
   // and use it
   int main() {
      emp v;
      get_date(v);
      return 0;
   }

rather than:

   emp get_date(void) {
      emp ret;
      // ... do the stuff you need
      return ret;
   }
   // and use it
   int main() {
      emp v = get_date();
      return 0;
   }

Why?
The second example (unless your compiler is really smart) involves copying the members of the structure into a
temporary emp which is then copied into v. If emp has complex members which are classes, this may involve quite an overhead.
The first example only uses one emp[/green] and will execute much faster.
Just a hint, just a thought.
(There is also the consideration that the first example allows the function to be changed to return a value which indicates that it was successful or otherwise).

Roger J Coult
Allied Laboratory Services Limited
Grimsby, UK

 

[marsd]

struct emp *get_data(void) {
struct emp *new = NULL;


          new = malloc(sizeof(struct emp));
          if (new) {
              printf("Enter Employer's Name, Salary: ");
              scanf("%s %f", new->empname, new->salary);
              get_date();
              //other work here
              return new;
           }
          printf("ERROR: malloc(), out of memory??\n");
          return NULL;
          //or exit
}

 

[Cagliostro]

marsd, how does variable new work with comments //?

Ion Filipski

 

[Salem]

> how does variable new work with comments //?
Either
A C compiler extension to allow C++ style comments
A C99 compatible compiler.

--

 

[marsd]

Works fine with gcc , but point taken.