C Expert Programming Chapter 4 The Shocking Fact: Arrays and Pointers Are Not the Same 4.5 Other Differences Between Arrays and Pointers

/*Another difference between arrays and pointers
*Poems array
*Save the address of the data to save data
*indirect access data, first get the content of the pointer, directly access the data, A [i] is just the only thingSimply take a+i as the address to get the data
as the address, and then extract the data from this address
If the pointer has a subscript [i], add i as the address to the content of the pointer
and extract from itdata
*usually used for dynamic data structures typically used to store a fixed number of elements of the same data type
*relevant functions are malloc(), free() implicit allocation and deletion
*usually refers to anonymousThe data itself is the variable name
*/
/* Both arrays and pointers can be initialized with string constants in their definitions.But the underlying mechanism is different
*When defining a pointer, the compiler does not allocate space for the object pointed to by the pointer, it just allocates space for the pointer itself, unless
* is defined while assigning a pointer to aString constants are initialized.
*/
/* Allocate memory space for both p and "breakfruit" */
char *p = "breadfruit";
/* In ANSI C, the character created by initializing pointersString constants are defined as read-only.If you try to modify the value of this
* character through the pointer, the program will exhibit undefined behavior.
*/
float *pip = 3.14; /* ERROR!Can't compile */
/* Note that this is only true for string constants, don't expect to allocate space for constants like floating point numbers */

/*Arrays can also be initialized with string constants*/
char a[] = "gooseberry";
/*In contrast to pointers, arrays initialized with string constants can be modified.
*Individual characters can be changed later.
*/
For example:
strncpy(a, "black", 5);