Questions "pointers"

1. How are arguments passed to functions in C: by-value or by-reference? And what does that mean?
   Hint: C syntax → argument passing.
2. If double x=1.23, what is *(&x)?
3. What is NULL? Hint: null pointer.
4. What happens to variables declared inside a function when the function exits (returns)?
5. What is a static variable? Hint: static variable.
6. What will the following three programs print out and why?

   #include<stdio.h>
   void f(int i){i=0;}
   int main(){
   	int i=1; f(i); printf("i=%i\n",i);
   	return 0; }
   

   #include<stdio.h>
   void f(int* i){*i=0;}
   int main(){
   	int i=1; f(&i); printf("i=%i\n",i);
   	return 0; }
   

   #include<stdio.h>
   void f(int* i){i=NULL;}
   int main(){
   	int i=1; f(&i); printf("i=%i\n",i);
   	return 0; }
   

7. If you pass an array to a function with the signature void f(double a[]) – what is actually passed to the function:
   1. a copy of the whole array?
   2. the pointer a to the first element of the array?
   3. a copy of the pointer to the first element?
   4. something else?
   Hint: C syntax → argument passing → array parameters.
8. When the function with the signature void f(double a[]) gets the array as parameter – can it figure out the size of the array?
9. If you declare an array as int a[5]; and then try a[999]=1; what will might happen? Hint: Segmentation fault / causes.
10. If you declare an i) static, ii) variable-length, iii) dynamic array inside a function, can the function return it?