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Types of Arrays in C

Arrays in C are classified by their number of dimensions — how many indices are needed to access an element.

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1. One-Dimensional Array (1D)

The simplest array — stores elements in a single row. One index is enough to access any element. Syntax: 
data_type array_name[size];
Example: 
#include <stdio.h>
int main() {
    int numbers[5] = {10, 20, 30, 40, 50};
    for (int i = 0; i < 5; i++) {
        printf("%d ", numbers[i]);
    }
    return 0;
}
// Output: 10 20 30 40 50

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2. Two-Dimensional Array (2D)

Stores elements in rows and columns — like a matrix or table. Two indices are needed: [row][column]. Syntax: 
data_type array_name[rows][columns];
Example: 
#include <stdio.h>
int main() {
    int matrix[2][3] = {{1, 2, 3}, {4, 5, 6}};
    for (int i = 0; i < 2; i++) {
        for (int j = 0; j < 3; j++) {
            printf("%d ", matrix[i][j]);
        }
        printf("\n");
    }
    return 0;
}
Output: 
1 2 3
4 5 6
Memory layout of matrix[2][3]: 
       Col 0  Col 1  Col 2
Row 0:   1      2      3
Row 1:   4      5      6

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3. Multi-Dimensional Array

Has more than two dimensions. Think of it as an array of 2D arrays. Used for complex data structures like 3D matrices or cubic grids. Syntax of a 3D array: 
data_type array_name[depth][rows][columns];
Example: 
#include <stdio.h>
int main() {
    int cube[2][2][2] = {
        {{1, 2}, {3, 4}},
        {{5, 6}, {7, 8}}
    };
    for (int i = 0; i < 2; i++) {
        for (int j = 0; j < 2; j++) {
            for (int k = 0; k < 2; k++) {
                printf("%d ", cube[i][j][k]);
            }
            printf("\n");
        }
        printf("\n");
    }
    return 0;
}
Output: 
1 2
3 4

5 6
7 8

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Comparison

TypeIndicesAccessUse Case
1D1arr[i]List of values
2D2arr[i][j]Tables, matrices
3D3arr[i][j][k]3D grids