Thread: How to get Extern struct to work properly ?

Apparently I failed to Call my struct. I have header file (header.h) where i defined my struct .
Header.h

Code:

struct theVar {
float x1, y1;
};
extern struct theVar global;


...


struct theVar compute (float x, float y){
  float x1 = x + y;
  float y1 = x * y;


  struct theVar result;
  result.x1;
  result.y1;
  return result;
}

and then in my C file, I call them :
file1.c

Code:

#include <header.h>
struct theVar global;


int main (){
 
struct theVar global = compute(3,4);


printf("x1 = %f \n", global.x1 );
printf("y1 = %f \n", global.y1);
}

But my program failed to call the value. What did I miss ?

Originally Posted by laserlight

It doesn't look like you need a global struct in the first place: you have a local struct named global to store the return value from compute, and this should work, although it also means that your global struct named global remains unused. If you really want to use the global struct instead, then just write:

Code:

global = compute(3, 4);

But again it looks like you don't need a global struct. You should avoid global variables. (Actually, since you didn't spot the declaration of a local variable shadowing the global variable, I daresay you must not use your own global variables as you presently lack sufficient skill in C to use them well and appropriately.)

hey , you reply to me again. thanks a lot for the suggestion ! Also, again for a few times now.. what a kind supportive word. I'm doing my best at school. wish me luck