Skip to content

Array Introduction

Arrays in C are fundamental data structures that allow you to store multiple values of the same data type under a single variable name. They provide a convenient way to work with collections of data in a program. Here’s an introduction to arrays in C:

  1. Definition:
    • An array in C is a collection of elements of the same data type stored sequentially in memory. Each element in the array occupies a contiguous block of memory, and elements are accessed using an index.
    • Arrays can be one-dimensional, multi-dimensional, or even arrays of arrays (also known as multi-dimensional arrays).
  2. Syntax:
    • The syntax for declaring an array in C is as follows:

data_type array_name[array_size];

  • data_type specifies the type of data that the array will hold (e.g., int, float, char).
  • array_name is the identifier for the array variable.
  • array_size specifies the number of elements the array can hold. It must be a constant expression or a literal indicating the size of the array.
  • Initialization:
  • Arrays can be initialized at the time of declaration or later in the program.
  • When initializing at declaration, you can specify the initial values enclosed in curly braces {}.
  • If fewer initializers are provided than the size of the array, the remaining elements are automatically initialized to zero (for numeric types) or null character (‘\0’) for character arrays.
  • Accessing Elements:
  • Elements of an array are accessed using an index, which is an integer value representing the position of the element within the array.
  • The index of the first element in C arrays is 0, and the index of the last element is array_size – 1.
  • Example:

Here’s an example of declaring, initializing, and accessing elements of an array in C:

#include <stdio.h>

int main() {

    // Declaration and initialization of an integer array

    int numbers[5] = {10, 20, 30, 40, 50};

    // Accessing and printing array elements

    printf(“First element: %d\n”, numbers[0]);   // Output: First element: 10

    printf(“Third element: %d\n”, numbers[2]);   // Output: Third element: 30

    return 0;

}

  • Usage:
  • Arrays are widely used in C for various purposes, including storing lists of data, implementing data structures (like stacks and queues), and performing computations on collections of values.
  • They provide a more efficient way to work with large amounts of data compared to individual variables.

Arrays are an essential concept in C programming, providing a foundation for many algorithms and data structures. Understanding how to declare, initialize, and access elements of arrays is crucial for writing efficient and scalable programs in C.