C/C++中的数组和指针的比较与例子

什么是数组？

数组是存储连续内存位置的相同类型的多个项目的集合。每个元素的位置可以通过在基值上加上一个偏移量来计算，即数组第一个元素的内存位置。

句法：

datatype var_name[size_of_array] = {elements};

例子：

C++

#include 
using namespace std;
int main()
{
    int i, j;
  
    // Declaring array
    int a[5];
  
    // Insert elements in array
    for (i = 0; i < 5; i++) 
    {
        a[i] = i + 1;
    }
  
    // Print elements of array
    for (j = 0; j < 5; j++) 
    {
        cout << a[j] << " ";
    }
    return 0;
}

输出

1 2 3 4 5 

什么是指针？

指针是地址的符号表示。它存储变量的地址或内存位置。指针使程序员能够创建和操作动态数据结构。

句法：

datatype *var_name;

例子：

C++

// C++ program to implement array
#include 
using namespace std;
  
// Driver code
int main()
{
    int a = 20;
    int* ptr;
    ptr = &a;
    cout << a << " " << ptr << 
            " " << *ptr;
    return 0;
}

输出

20 0x7ffe2ae2d4ec 20

数组和指针的比较

指针可用于访问数组元素，使用指针算法访问整个数组，使访问速度更快。数组和指针之间还有一些其他差异，这些差异将在下表中讨论。

S No.	Array	Pointer
1	type var_name[size];	type * var_name;
2	Collection of elements of similar data type.	Store the address of another variable.
3	The array can be initialized at the time of definition.	Pointers cannot be initialized at definition.
4	An array can decide the number of elements it can store.	The pointer can store the address of only one variable.
5	Arrays are allocated at compile time.	Pointers are allocated at run-time.
6	Memory allocation is in sequence.	Memory allocation is random.
7	Arrays are static in nature i.e. they cannot be resized according to the user requirements.	Pointers are dynamic in nature i.e. memory allocated can be resized later.
8	An array of pointers can be generated.	A pointer to an array can be generated.
9	Java Support the concept of an array.	Java Does not support pointers.
10	An array is a group of elements.	Python is not a group of elements.