/**
 * @file funcpointer.cpp
 * @brief This file demonstrates the usage of function pointers in C++.
 *
 * The code defines two struct types, Student and Employee, and a linked list
 * implementation using function pointers. It showcases how function pointers
 * can be used to print the data stored in the linked list nodes. The main
 * function adds nodes to the linked list, prints the data using function
 * pointers, and measures the elapsed time. Finally, it cleans up the memory
 * allocated for the linked list.
 */
#include <chrono>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

// Define two different struct types.
typedef struct Student {
  char name[50];

  static void print(void *node) {
    Student *s = (Student *)node;
    printf("Student:\n");
    printf("Name: %s\n", s->name);
  }
} Student;

typedef struct Employee {
  int id;
  static void print(void *node) {
    Employee *e = (Employee *)node;
    printf("Employee:\n");
    printf("Employee ID: %d\n", e->id);
  }
} Employee;

// Functions to print the data.

enum { STUDENT, EMPLOYEE } type;

// Define a node which can hold either of the structs and a function pointer to
// print them.
typedef struct node {
  void *data;
  int type;
  void (*print)(void *);
} Node;

int main() {
  Node arr[2];
  int nodeCount = 0;

  Student s1 = {"Alice"};
  arr[nodeCount].data = &s1;
  arr[nodeCount].print = Student::print;
  arr[nodeCount].type = STUDENT;
  nodeCount++;

  Employee e1 = {25};
  arr[nodeCount].data = &e1;
  arr[nodeCount].print = Employee::print;
  arr[nodeCount].type = EMPLOYEE;
  nodeCount++;

  // Print loop using if-else
  for (int i = 0; i < nodeCount; i++) {
    if (arr[i].type == STUDENT) {
      Student::print(arr[i].data);
    } else {
      Employee::print(arr[i].data);
    }
  }

  // Print loop using function pointers
  for (int i = 0; i < nodeCount; i++) {
    arr[i].print(arr[i].data);
    printf("\n");
  }

  return 0;
}