Array in C

Array in C: In C programming, an array is a collection of elements of the same type placed in contiguous memory locations. This allows for efficient indexing and manipulation of data. Here’s a detailed explanation of arrays in C along with the common operations performed on them:

Declaring an Array in C

To declare an array in C, you specify the type of its elements and the number of elements required by an array.

int myArray[10]; // Declares an array of 10 integers

Initializing an Array in C

You can initialize an array at the time of declaration.

int myArray[5] = {1, 2, 3, 4, 5}; // Initializes an array with values 1 to 5

If you don’t initialize all the elements, the remaining elements will be initialized to 0.

int myArray[5] = {1, 2}; // Remaining elements are 0

Accessing Elements of an Array in C

Array elements are accessed using their index. The index of the first element is 0.

myArray[0] = 10; // Sets the first element to 10
int value = myArray[1]; // Gets the second element

Common Operations on Array in C

Traversing an Array

Looping through all the elements of the array.

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

Inserting an Element

To insert an element at a specific position, shift the elements and then assign the value.

int pos = 2; // Position to insert the element
int value = 99;
for (int i = 4; i >= pos; i--) {
    myArray[i + 1] = myArray[i];
}
myArray[pos] = value;

Deleting an Element

To delete an element at a specific position, shift the elements to fill the gap.

int pos = 2; // Position of the element to delete
for (int i = pos; i < 4; i++) {
    myArray[i] = myArray[i + 1];
}

Searching for an Element

To search for an element, you can use a loop to check each element.

int value = 99;
int found = -1; // Will hold the index of the found element
for (int i = 0; i < 5; i++) {
    if (myArray[i] == value) {
        found = i;
        break;
    }
}

Updating an Element

To update an element at a specific index, assign a new value to that index

myArray[2] = 50; // Updates the third element to 50

Multidimensional Arrays in C

C also supports multidimensional arrays, which are arrays of arrays.

int matrix[3][4]; // A 3x4 matrix (2D array)

Initializing a multidimensional array:

int matrix[3][4] = {
    {1, 2, 3, 4},
    {5, 6, 7, 8},
    {9, 10, 11, 12}
};

Accessing elements in a multidimensional array:

int value = matrix[1][2]; // Gets the element in the 2nd row and 3rd column

Example Program

Here’s a complete example program that demonstrates the various operations on arrays.

#include <stdio.h>

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

    // Traversing the array
    printf("Array elements: ");
    for (int i = 0; i < 5; i++) {
        printf("%d ", myArray[i]);
    }
    printf("\n");

    // Inserting an element
    int pos = 2;
    int value = 99;
    for (int i = 4; i >= pos; i--) {
        myArray[i + 1] = myArray[i];
    }
    myArray[pos] = value;

    // Traversing the array after insertion
    printf("Array elements after insertion: ");
    for (int i = 0; i < 6; i++) {
        printf("%d ", myArray[i]);
    }
    printf("\n");

    // Deleting an element
    pos = 3;
    for (int i = pos; i < 5; i++) {
        myArray[i] = myArray[i + 1];
    }

    // Traversing the array after deletion
    printf("Array elements after deletion: ");
    for (int i = 0; i < 5; i++) {
        printf("%d ", myArray[i]);
    }
    printf("\n");

    // Searching for an element
    value = 4;
    int found = -1;
    for (int i = 0; i < 5; i++) {
        if (myArray[i] == value) {
            found = i;
            break;
        }
    }
    if (found != -1) {
        printf("Element %d found at index %d\n", value, found);
    } else {
        printf("Element %d not found\n", value);
    }

    // Updating an element
    myArray[2] = 50;

    // Traversing the array after updating
    printf("Array elements after updating: ");
    for (int i = 0; i < 5; i++) {
        printf("%d ", myArray[i]);
    }
    printf("\n");

    return 0;
}

This program demonstrates the basic operations: traversal, insertion, deletion, searching, and updating elements in an array. Understanding these fundamental operations will help you work efficiently with arrays in C.