What is the difference between array pointer and array reference?

There are the following differences between array pointers and array references: Dereference required: Array pointers need to be dereferenced, while array references do not. Pointer arithmetic: Array pointers support pointer arithmetic, while array references do not. Address: The array pointer stores the address of the first element of the array, but the array reference is not an address. Const kval: An array pointer can point to a const kval, but an array reference cannot. Array size: Array pointers do not store the array size, whereas array references implicitly contain the array size.

Array pointers and array references: detailed explanation of the difference

In programming, array pointers and array references are both used to access arrays elements, but there are subtle differences between them.

Array pointer

The array pointer is a pointer variable pointing to the first element of the array. It allows you to access array elements indirectly through pointers.

int arr[] = {1, 2, 3, 4, 5};
int *ptr = arr; // ptr 指向 arr 的首元素

*ptr; // 解引用 ptr 并访问 arr[0]

Array reference

An array reference is a method of directly accessing array elements using square bracket ([]) syntax. It does not require explicit use of pointers.

int arr[] = {1, 2, 3, 4, 5};

arr[0]; // 直接访问 arr 的首元素

Difference

• Dereference required: Array pointers need to be dereferenced before use, while array references do not.
• Pointer Arithmetic: Array pointers support pointer arithmetic, allowing you to navigate within the array using the ++ and -- operators. Array references do not support this feature.
• Address: The array pointer stores the address of the first element of the array, while the array reference is not an address.
• Constant kval: Array pointers can point to const kval, but array references cannot.
• Array size: Array pointers do not store the array size, while array references implicitly contain the array size.

Practical Case

Let’s examine an example using array pointers and array references to show their practical differences:

#include <stdio.h>

int main() {
    int arr[] = {1, 2, 3, 4, 5};
    int *ptr = arr;

    // 使用数组指针访问数组元素
    printf("%d\n", *ptr); // 输出 1

    // 使用指针算术在数组中导航
    ptr++;

    // 再次使用数组指针访问数组元素
    printf("%d\n", *ptr); // 输出 2

    // 使用数组引用访问数组元素
    printf("%d\n", arr[2]); // 输出 3
    
    return 0;
}

In this example, array pointer ptr is used to access the first element of array arr and navigate through the array through pointer arithmetic. At the same time, the array reference arr[2] directly accesses the third element of the array.

The above is the detailed content of What is the difference between array pointer and array reference?. For more information, please follow other related articles on the PHP Chinese website!