Array Pointer (Pointer To Array) in C Programming Language

In this tutorial, we will learn about array pointers in the C programming language. Array pointers, also known as pointers to arrays, are pointers that point to the first element of an array. They are useful when working with functions that require passing arrays or for dynamic memory allocation.

Declaring an array pointer:

To declare a pointer to an array, specify the data type, followed by an asterisk (*) for the pointer, the name of the pointer, and the size of the array enclosed in square brackets.

int (*arrayPointer)[5]; // Declare a pointer to an array of 5 integers

In this example, arrayPointer is a pointer to an array of 5 integers. It can be used to point to any array with 5 integer elements.

Assigning an array to a pointer:

To assign the address of an array to a pointer, use the name of the array (which is a pointer to the first element).

int myArray[5] = {1, 2, 3, 4, 5};
arrayPointer = &myArray;

Accessing elements using an array pointer:

To access elements in an array using an array pointer, use the pointer name followed by the index enclosed in square brackets.

int firstElement = (*arrayPointer)[0]; // Access the first element of the array
int thirdElement = (*arrayPointer)[2]; // Access the third element of the array

Example: Iterating over an array using an array pointer

Here's an example demonstrating how to iterate over an array using an array pointer:

#include <stdio.h>

int main() {
    int myArray[5] = {1, 2, 3, 4, 5};
    int (*arrayPointer)[5] = &myArray;

    // Iterate over the array using an array pointer
    for (int i = 0; i < 5; i++) {
        printf("%d ", (*arrayPointer)[i]);
    }

    return 0;
}

The output will be:

1 2 3 4 5

That's it for our tutorial on array pointers in the C programming language. Understanding how to use pointers with arrays is essential when working with dynamic memory allocation, passing arrays to functions, or when passing multidimensional arrays as function arguments.

Pointer to array in C example:

#include <stdio.h>

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

    // Accessing elements using pointer
    printf("Element at index 2: %d\n", *(ptrToNumbers + 2));

    return 0;
}

Declares an array numbers and a pointer ptrToNumbers pointing to its first element.

How to declare and use array pointers in C:

#include <stdio.h>

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

    // Using array pointer
    printf("First element: %d\n", *ptrToNumbers);

    return 0;
}

Declares an array pointer and demonstrates its usage.

Passing array pointers to functions in C:

#include <stdio.h>

// Function taking an array pointer
void printArray(int *arr, int size) {
    for (int i = 0; i < size; ++i) {
        printf("%d ", arr[i]);
    }
    printf("\n");
}

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

    // Passing array pointer to a function
    printArray(ptrToNumbers, 5);

    return 0;
}

Demonstrates passing an array pointer to a function.

Dynamic allocation of arrays using pointers in C:

#include <stdio.h>
#include <stdlib.h>

int main() {
    int size = 5;
    int *dynamicArray = (int *)malloc(size * sizeof(int));

    // Remember to free memory when done
    free(dynamicArray);

    return 0;
}

Allocates memory dynamically for an array using pointers.