> ## Documentation Index
> Fetch the complete documentation index at: https://learn.acadlink.app/llms.txt
> Use this file to discover all available pages before exploring further.

# Pointers and Arrays

> Accessing array elements with pointers and array of pointers

# Pointers and Arrays in C

In C, the **name of an array is a pointer** to its first element. This tight relationship means you can traverse and manipulate arrays entirely through pointer arithmetic.

```c theme={null}
int arr[5] = {10, 20, 30, 40, 50};
int *ptr = arr;   // same as: int *ptr = &arr[0];
```

***

## Accessing Array Elements via Pointer

```c theme={null}
#include <stdio.h>

int main() {
    int num[5] = {10, 20, 30, 40, 50};
    int *ptr = num;

    for (int i = 0; i < 5; i++) {
        printf("num[%d] = %d\t Address = %p\n", i, *(ptr + i), (ptr + i));
    }
    return 0;
}
```

`*(ptr + i)` and `num[i]` are completely equivalent — the compiler translates `num[i]` to `*(num + i)` internally.

***

## Array of Pointers

An array where each element is a pointer:

```c theme={null}
data_type *array_name[size];

int *ptr[3];    // array of 3 integer pointers
```

### Example 1: Array of Integer Pointers

```c theme={null}
#include <stdio.h>

int main() {
    int a = 10, b = 20, c = 30;
    int *ptr[3];

    ptr[0] = &a;
    ptr[1] = &b;
    ptr[2] = &c;

    for (int i = 0; i < 3; i++) {
        printf("Value of ptr[%d]: %d\n", i, *ptr[i]);
    }
    return 0;
}
```

**Output:**

```
Value of ptr[0]: 10
Value of ptr[1]: 20
Value of ptr[2]: 30
```

### Example 2: Array of String Pointers

Useful for storing a list of strings without a 2D character array:

```c theme={null}
#include <stdio.h>

int main() {
    char *names[] = {"Rahul", "Parvej", "Aman"};

    for (int i = 0; i < 3; i++) {
        printf("Name[%d]: %s\n", i, names[i]);
    }
    return 0;
}
```

**Output:**

```
Name[0]: Rahul
Name[1]: Parvej
Name[2]: Aman
```

***

## `arr[i]` vs `*(arr + i)`

These two are identical in C:

```c theme={null}
int arr[] = {5, 10, 15};

arr[2]       // 15
*(arr + 2)   // 15  — pointer arithmetic equivalent
```

***

## Key Points

* `arr` (array name) decays to `&arr[0]` when used in an expression
* `sizeof(arr)` gives the total array size; `sizeof(ptr)` gives only the pointer size
* You can increment a pointer (`ptr++`) but **not** an array name (`arr++` is illegal)