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

#define MYDEF a=a+1
#define MAX 5

int globalStuff = 1000;

struct mycomplex {
  int re;
  int im;
};

typedef struct mycomplex tcplx;

union myunion {
  int i;
  char d;
};

struct o {
  int select;
  union myunion u;
};

void myf(int *a) {
  *a = 50;
}

int myf2(int a) {
  a = 50;
  return a;
}

static int x=66;

int* mypint() {
  return &x;
}

tcplx *create_cplx(int re, int im) {
  tcplx *cp = (tcplx*) malloc (sizeof(tcplx));
  // memset(cp, 0, sizeof(tcplx);
  cp->re = re;
  cp->im = im;
  return cp;
}

int main(void) {
  int a = 2;
  MYDEF;
  char c = 'c';
  double d = 3.14;

  struct mycomplex cplx;
  cplx.re = 1;
  cplx.im = 2;
  tcplx cplx2;
  cplx2 = cplx;
  
  printf("Variable a=%d %c %g %lu\n", a, c, d, sizeof(a));
  printf("Variable cplx.re=%d cplx.im=%d\n", cplx.re, cplx.im);
  cplx.im = cplx.re + a;
  printf("Variable cplx.re=%d cplx.im=%d\n", cplx.re, cplx.im);

  printf("Variable cplx2.re=%d cplx2.im=%d\n", cplx2.re, cplx2.im);  
  
  union myunion u;
  u.d=10.2;
  printf("Size of union %lu Size of struct %lu\n",
	 sizeof(union myunion), sizeof(struct mycomplex));

  int arr[MAX] = {1, 2, 3, 4, 5};
  int arr2[MAX];
  printf("arr=");
  for(int i=0; i < MAX; i++) {
    printf("%d ", arr[i]);
    arr2[i] = arr[i] + 2;
  }
  printf("\n");

  arr[3] = 10;

  printf("arr2=");
  for(int i=0; i < MAX; i++) {
    printf("%d ", *(arr2+i));
  }
  printf("\n");
  int h = 100;
  printf("h = %d\n", h);
  *(arr2+2) = 10;
  printf("arr2[2] = %d\n", arr2[2]);    

  int *pa = &a;
  int **ppa = &pa;

  printf("a=%d pa=%p ppa=%p\n", a, pa, ppa);

  printf("*pa = %d\n", *pa);

  a = 100;

  printf("*pa = %d\n", *pa);

  *pa = 1000;
  
  printf("**ppa = %d\n", **ppa);

  tcplx *pcplx = &cplx2;

  printf("Variable pcplx->re=%d pcplx->im=%d (*pcplx).im=%d\n", pcplx->re, pcplx->im, (*pcplx).re);

  pcplx->im = 100;

  printf("Variable cplx2.re=%d cplx2.im=%d\n", cplx2.re, cplx2.im);    

  // myf(&a);

  a = myf2(a);

  printf("a=%d\n", a);

  char *str = "mystring";

  printf("str=%s len=%lu\n", str, strlen(str));

  printf("a as casted pointer to float: %f\n", *((float*)pa));
  printf("a as float: %f\n", (float)a);
  printf("a as casted pointer to char: %c\n", *((char*)pa));  
  a = 65;
  printf("a as casted pointer to char: %c\n", *((char*)pa));
  printf("a as hex: %x\n", a);

  void *vp = (void*)&a;

  printf("a=%d\n", *((int*)vp));

  printf("x=%d\n", *mypint());

  printf("x=%d\n", x);

  tcplx *cp = create_cplx(99, 88);

  printf("Variable cp->re=%d cp->im=%d\n", cp->re, cp->im);  

  printf("Pointer to cp = %p &cplx2=%p\n", cp, &cplx2);

  //free(cp);

  //printf("Variable cp->re=%d cp->im=%d\n", cp->re, cp->im);    
  //printf("Pointer to cp = %p &cplx2=%p\n", cp, &cplx2);  
  
  return 0;
}