fork download 
  1. #include <stdio.h>
  2.  
  3. struct Structure {
  4.     int a;
  5.     void (*function)(struct Structure *);
  6. };
  7.  
  8. void foo(struct Structure *a) {
  9.     if (a->function == NULL) a->function = foo;
  10.     a->a++;
  11.     printf("%d\n", a->a);
  12. }
  13.  
  14. int main(void) {
  15.     struct Structure a = {42, foo};
  16.     struct Structure b = {0}; // don't call b.function just yet!!
  17.     a.function(&b); // foo(&b)
  18.     b.function(&a); // foo(&a)
  19. }
  20.  
Success #stdin #stdout 0s 5520KB
comments (?)
stdin 
Standard input is empty
stdout 
1
43
https://ideone.com/7E74gb
function pointer inside structure
language:
C (gcc 8.3)
created:
4 years ago
visibility:
secret

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!