In C programming, an array is a collection of similar data types, such as integers, floating-point numbers, or characters. An array allows us to store a fixed-size sequential collection of elements, where each element can be accessed by an index or a subscript.

Declaring an array in C: To declare an array in C, we need to specify the data type of the array and the number of elements in the array. The syntax for declaring an array in C is as follows:

data_type array_name[array_size];

For example, to declare an array of integers with 5 elements, we can use the following code:

int numbers[5];

Initializing an array in C: To initialize an array in C, we can use curly braces to enclose a comma-separated list of values. The number of values in the list should be equal to or less than the number of elements in the array. The syntax for initializing an array in C is as follows:

data_type array_name[array_size] = {value1, value2, ..., valueN};

For example, to initialize an array of integers with 5 elements, we can use the following code:

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

Accessing elements of an array in C: To access an element of an array in C, we use the array name and the index or subscript of the element we want to access. The index or subscript starts at 0 and goes up to the number of elements in the array minus 1. The syntax for accessing an element of an array in C is as follows:

array_name[index];

For example, to access the third element of an array of integers called numbers, we can use the following code:

int third_element = numbers[2];

This code assigns the value of the third element of the array numbers (which has an index of 2) to the variable third_element.

Examples of using arrays in C: Here are some examples of how to use arrays in C:

Example 1: Finding the sum of elements of an array

#include <stdio.h>

int main()
{
    int numbers[5] = {1, 2, 3, 4, 5};
    int sum = 0;

    for (int i = 0; i < 5; i++) {
        sum += numbers[i];
    }

    printf("The sum of the elements of the array is %d\n", sum);

    return 0;
}

This code declares an array of integers with 5 elements, initializes the array with some values, and calculates the sum of the elements of the array using a for loop.

Example 2: Sorting an array of integers in ascending order

#include <stdio.h>

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

    for (int i = 0; i < 5; i++) {
        for (int j = i + 1; j < 5; j++) {
            if (numbers[i] > numbers[j]) {
                int temp = numbers[i];
                numbers[i] = numbers[j];
                numbers[j] = temp;
            }
        }
    }

    printf("The sorted array in ascending order is:\n");

    for (int i = 0; i < 5; i++) {
        printf("%d ", numbers[i]);
    }

    printf("\n");

    return 0;
}