C 1D and 2D array

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1D Array in C

An array in C is a collection of elements of the same type, stored at contiguous memory locations. Arrays can store primitive types such as int, char, double, float, and derived types like pointers and structures. Arrays are a fundamental data structure that allows efficient storage and access of multiple items of the same type using an index.

Properties of Array

1. Same Data Type: Each element of an array is of the same data type and occupies the same amount of memory.

2. Contiguous Memory Locations: Elements are stored in contiguous memory locations.

3. Random Access: Elements can be accessed directly using their index.

Advantages of C Array

1.Code Optimization: Less code is required to access and manipulate data.

2. Ease of Traversing: Elements can be easily retrieved using loops.

3. Ease of Sorting: Sorting elements requires minimal code.

4. Random Access: Any element can be accessed directly using its index.

Disadvantages of C Array

1. Fixed Size: The size of the array is fixed at the time of declaration and cannot be changed.

Declaration and Initialization of 1D Array

An array is declared by specifying the data type, array name, and size.

Syntex:

data_type array_name[array_size];

Example:

int marks[5];

Initialization

An array can be initialized using index values.

int marks[5] = {90, 85, 78, 92, 88};

If you want to initialize an array without specifying values for all elements, the remaining elements will be initialized to zero.

int marks[5] = {90, 85}; // marks[2] to marks[4] will be 0

Example of Accessing Array Elements

#include <stdio.h>

int main() {
    int marks[5] = {90, 85, 78, 92, 88};
    for (int i = 0; i < 5; i++) {
        printf("Mark of subject %d is %d\\n", i+1, marks[i]);
    }
    return 0;
}

Output:

Mark of subject 1 is 90
Mark of subject 2 is 85
Mark of subject 3 is 78
Mark of subject 4 is 92
Mark of subject 5 is 88

2D Array in C

A two-dimensional (2D) array is an array of arrays, organized in a matrix of rows and columns. It is useful for representing data in tabular form.

Declaration of 2D Array

Syntex:

data_type array_name[rows][columns];

Example:

int matrix[4][3];

Initialization of 2D Array

Unlike 1D arrays, at least the second dimension must be specified during declaration and initialization.

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

Example: Accessing 2D Array Elements


#include <stdio.h>

int main() {
    int matrix[4][3] = {
        {1, 2, 3},
        {4, 5, 6},
        {7, 8, 9},
        {10, 11, 12}
    };
    for (int i = 0; i < 4; i++) {
        for (int j = 0; j < 3; j++) {
            printf("Element at [%d][%d] is %d\\n", i, j, matrix[i][j]);
        }
    }
    return 0;
}

Output:

Element at [0][0] is 1
Element at [0][1] is 2
Element at [0][2] is 3
Element at [1][0] is 4
Element at [1][1] is 5
Element at [1][2] is 6
Element at [2][0] is 7
Element at [2][1] is 8
Element at [2][2] is 9
Element at [3][0] is 10
Element at [3][1] is 11
Element at [3][2] is 12

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