C.Tutorial

Arrays in C

Arrays in C are used to store multiple values in a single variable. They allow you to store values of the same data type in a contiguous block of memory.

Definition

An array is a collection of variables of the same data type that are stored in contiguous memory locations. Each element in an array can be accessed using an index.

Syntax:

                        
data_type array_name[array_size];

Example 1: Declaring and Initializing an Array

                        
                            {% raw %}
#include <stdio.h>
int main() 
{
    int numbers[5] = {1, 2, 3, 4, 5}; // Array initialization
        
    for (int i = 0; i < 5; i++) {
        printf("Element %d: %d\n", i, numbers[i]);
    }
        
    return 0;
}
            {% endraw %}

Output

Element 0: 1
Element 1: 2
Element 2: 3
Element 3: 4
Element 4: 5

Array Types

C supports different types of arrays based on the data they store:

int[]: Array of integers.
float[]: Array of floating-point numbers.
char[]: Array of characters.
double[]: Array of double precision floating-point numbers.

Example 2: Array of Floating-Point Numbers

                        
                            {% raw %}
#include <stdio.h>
int main() 
{
    float numbers[3] = {3.14, 2.71, 1.41}; // Array of floats
        
    for (int i = 0; i < 3; i++) {
        printf("Element %d: %.2f\n", i, numbers[i]);
    }
        
    return 0;
}
            {% endraw %}

Output

Element 0: 3.14
Element 1: 2.71
Element 2: 1.41

Example 3: Using a Character Array

                        
                            {%raw%}
#include <stdio.h>
int main() 
{
    char name[10] = "John"; // Array of characters (string)
        
    printf("Name: %s\n", name);
        
    return 0;
}
            {%endraw%}

Output

Name: John

Key Points

Arrays must be declared with a fixed size or initialized with a set number of values.
Array indices start from 0.
Arrays can be multi-dimensional (e.g., 2D arrays).
Always ensure the array size is large enough to hold all the values.
C does not perform bounds checking, so accessing an index outside the array range leads to undefined behavior.

Example 4: Multidimensional Array

                        
            {%raw%}
#include <stdio.h>
int main() 
{

    int matrix[2][2] = {{1, 2}, {3, 4}}; // 2D array
        
    for (int i = 0; i < 2; i++) {
         for (int j = 0; j < 2; j++) {
            printf("Element [%d][%d]: %d\n", i, j, matrix[i][j]);
       }
    }
        
    return 0;
}
{%endraw%}

Output

Element [0][0]: 1
Element [0][1]: 2
Element [1][0]: 3
Element [1][1]: 4