#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>

#define SIZE 20

typedef struct s1 {
    long ts;
    char location[SIZE];
    int temp;
} Reading;


// --------------------------------------------------
int main(int argc, char** argv) {

  // Allocate
  Reading *pointer = (Reading*)malloc(sizeof(Reading));

  // Check if allocation worked
  if ( ! pointer ) {
    fprintf(stderr,"Out of memory\n");
    return 1;
  }

  long time = 20;
  int  temp = 67;

  // Use the structure
  pointer->ts = time;  
  pointer->temp = temp;
  printf("Sample is (%ld,%d)\n", pointer->ts, pointer->temp);

  // Free
  free(pointer);

  // Common bug 1: Accessing memory that has been freed already
  // pointer is now dangling, could cause silent bug
  printf("BUG! BEFORE NULL! Sample is (%ld,%d)\n", pointer->ts, pointer->temp);

  // making sure that error will cause crash!
  pointer = NULL; // Good programming practice to set unused pointers to NULL
  printf("BUG! AFTER NULL! Sample is (%ld,%d)\n", pointer->ts,  pointer->temp);

  // Common bug 2: memory leaks
  pointer = (Reading*)malloc(sizeof(Reading)); // Allocate chunk 1
  pointer = (Reading*)malloc(sizeof(Reading)); // Allocate chunk 2
  free(pointer);
  // Can never free the memory allocated for chunk 1

  // The above problems get tricky with functions
  // When one function allocates space and other functions
  // are supposed to free it later on

  return 0;


}