A decent compiler will generate the same code for pointer accesses and array accesses and you should probably not be worrying about that level of performance.
In fact, without optimisation turned on, pointer code can be less efficient. Understanding why this happens is left as an exercise to the reader .
The default optimisation here is basically none at all. A label is something the compiler assigns at compile time. References The following sources were helpful in the preparation of this article: Pointer arithmetic and array indexing are equivalent. When applied to an array, sizeof operator will return the entire size of the array, whereas when applied to a pointer, it would return just the size of the pointer.
In other aspects, pointers and arrays are different. In one of your comments, you state: On the other hand, the semantics of pointers are quite different.
Consider this code snippet: But, most of the times, we are actually going to use less number of elements than we have allocated. Similarly, pointer arithmetic works on both arrays and pointers.
In C programming language, array indexing is done using pointer arithmetic i. From here the great difference between arrays and pointers in C stems. The pointer version will in general be faster but, at least to the uninitiated, somewhat harder to grasp immediately.
A pointer is just a regular variable that happens to hold the address of another variable inside. I always tend to prefer writing code for readability and only worrying about performance if it becomes an issue.
What is the difference between Pointers and Arrays? You only need to look at some of the code output by gcc in high optimisation modes to know that it is no longer true. Modern compilers are more than up to the task of figuring out that array operations and pointer operations can be turned into the same underlying machine code.
Does the difference affect me? Consider the following translations: Some of that code is very hard to understand but, once you do, its brilliance is evident. You can just take it as a fact: A variable in C is just a convenient, alphanumeric pseudonym of a memory location.
Once an array is defined, its size is fixed. Therefore in C, set of pointers that point to a set of memory locations that are consecutive, can be thought of as an array.A pointer in C is a typed integer variable that contains an address.
An address is an integer that maps to a memory cell. Pointers have the quality that adding or subtracting from them adds or subtacts addresses by the size in bytes of what the type is.
Int pointers add and subtract by the size of. Normal array vs Array of pointers [closed] Ask Question.
up vote 0 down vote favorite. Are there any advantage of using normal arrays over array of pointers(and vice-versa)? When should I use array of pointers and when should I avoid it? In college, everyone seems to be crazy about pointers.
I know std::vector is an easy way out, but it is. Pointers and arrays are strongly related. In fact, pointers and arrays are interchangeable in many cases. For example, a pointer that points to the beginning of an array can access that array by using either pointer arithmetic or array-style indexing.
The semantics of arrays in C dictate that the array name is the address of the first element of the array. Hence in the assignment to a, the 8th character of the array is taken by offsetting the value of array_place by 7, and moving the contents pointed to by the resulting address into the al register, and later into a.
On the other hand, the semantics of pointers are quite different. Pointer vs Array A pointer is a data type that holds a reference to a memory location (i.e.
a pointer variable stores an address of a memory location in which some data is stored). Arrays are the most commonly used data structure to store a collection of elements. The differences of arrays vs pointers are: pointer has no information of the memory size behind it (there is no portable way to get it) an array of incomplete type cannot be constructed.Download