Define functions in structs

Question

Can we define functions in structs in C programming language?

Answer 1

You can use only function pointers in C. Assign address of real function to that pointer after struct initialization, example:

#include 
#include 

struct unit
{
  int result;
  int (*add) (int x, int y);
};

int sumFunc(int x, int y) { return x + y; }

void *unitInit()
{
  struct unit *ptr = (struct unit*) malloc(sizeof(struct unit));
  ptr->add = &sumFunc;
  return ptr;
}

int main(int argc, char **argv)
{
  struct unit *U = unitInit();

  U->result = U->add(5, 10);

  printf("Result is %i\n", U->result);

  free(U);

  return 0;
}

Good example of using function pointers in a struct you can find here https://github.com/AlexanderAgd/CLIST Check header and then clist.c file.