3. Pointers and Arrays
|
| |
 In C, there is a strong relationship between pointers and arrays, strong enough that pointers and arrays should be discussed simultaneously. |
| Primitive arrays implemented in C using pointer to block of contiguous memory. |
Define an array size of 10, that is a block of 10 consecutive objects named a[0], a[1], ..., a[9].
|
| |
 |
int a[10], x;
int *pa;
pa = &a[0]; // pa contains the address of a[0]
pa = a; // Since the name of an array is a synonym
// for the location of the initial element
x = *pa; // will copy the contents of a[0] into x
|
|
| |
 |
| |
| The sizeof() Operator |
| |
For primitive types/variables, size of type in bytes:
|
sizeof(char); // 1
sizeof(double); // 8 (64-bit OS)
|
|
| |
For primitive arrays, size of array in bytes:Array length:
|
int arr[8]; // sizeof(arr) == 32 (64-bit OS)
long arr [5]; // sizeof(arr) == 40 (64-bit OS)
|
|
| |
Array length
|
/* needs to be on one line when implemented */
#define array _length(arr) ＼
( sizeof(arr) == 0? ＼
0 : sizeof(arr)/ sizeof((arr)[0]))
|
|
| |