One Dimensional Array and Multi-Dimensional Arrays
Arrays can be categorized based on their dimensions. The most common are one-dimensional arrays and multi-dimensional arrays, such as two-dimensional and three-dimensional arrays.
One-Dimensional Arrays
A one-dimensional array (often called a single-dimensional array) is the simplest form of an array. It is essentially a list of elements, all of the same type, stored in contiguous memory locations.
Declaration and Initialization
In C++:
// Declaration
int arr[5];
// Initialization
int arr[5] = {1, 2, 3, 4, 5};
// Accessing elements
cout << arr[0]; // Outputs: 1
arr[2] = 10; // Modifies the third element to 10
In Python:
# Declaration and initialization
arr = [1, 2, 3, 4, 5]
# Accessing elements
print(arr[0]) # Outputs: 1
arr[2] = 10 # Modifies the third element to 10
Traversing a One-Dimensional Array
In C++:
#include <iostream>
using namespace std;
int main() {
int arr[5] = {1, 2, 3, 4, 5};
// Traversing the array
for (int i = 0; i < 5; i++) {
cout << arr[i] << ” “;
}
cout << endl;
return 0;
}
In Python:
arr = [1, 2, 3, 4, 5]
# Traversing the array
for element in arr:
print(element, end=” “)
print()
Multi-Dimensional Arrays
Multi-dimensional arrays are arrays of arrays. The most common multi-dimensional arrays are two-dimensional arrays (matrices), but arrays can have any number of dimensions.
Two-Dimensional Arrays
A two-dimensional array is like a table or matrix where each element is identified by two indices: a row index and a column index.
Declaration and Initialization
In C++:
// Declaration
int arr[3][4];
// Initialization
int arr[3][4] = {
{1, 2, 3, 4},
{5, 6, 7, 8},
{9, 10, 11, 12}
};
// Accessing elements
cout << arr[0][1]; // Outputs: 2
arr[2][3] = 15; // Modifies the element at the third row and fourth column to 15
In Python:
# Declaration and initialization
arr = [
[1, 2, 3, 4],
[5, 6, 7, 8],
[9, 10, 11, 12]
]
# Accessing elements
print(arr[0][1]) # Outputs: 2
arr[2][3] = 15 # Modifies the element at the third row and fourth column to 15
Traversing a Two-Dimensional Array
In C++:
#include <iostream>
using namespace std;
int main() {
int arr[3][4] = {
{1, 2, 3, 4},
{5, 6, 7, 8},
{9, 10, 11, 12}
};
// Traversing the array
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 4; j++) {
cout << arr[i][j] << ” “;
}
cout << endl;
}
return 0;
}
In Python:
arr = [
[1, 2, 3, 4],
[5, 6, 7, 8],
[9, 10, 11, 12]
]
# Traversing the array
for row in arr:
for element in row:
print(element, end=” “)
print()
Three-Dimensional Arrays
A three-dimensional array is an array of arrays of arrays. It can be visualized as a cube of elements.
Declaration and Initialization
In C++:
// Declaration
int arr[2][3][4];
// Initialization
int arr[2][3][4] = {
{
{1, 2, 3, 4},
{5, 6, 7, 8},
{9, 10, 11, 12}
},
{
{13, 14, 15, 16},
{17, 18, 19, 20},
{21, 22, 23, 24}
}
};
// Accessing elements
cout << arr[1][2][3]; // Outputs: 24
arr[0][1][2] = 10; // Modifies the element at the first slab, second row, and third column to 10
In Python:
# Declaration and initialization
arr = [
[
[1, 2, 3, 4],
[5, 6, 7, 8],
[9, 10, 11, 12]
],
[
[13, 14, 15, 16],
[17, 18, 19, 20],
[21, 22, 23, 24]
]
]
# Accessing elements
print(arr[1][2][3]) # Outputs: 24
arr[0][1][2] = 10 # Modifies the element at the first slab, second row, and third column to 10
Traversing a Three-Dimensional Array
In C++:
#include <iostream>
using namespace std;
int main() {
int arr[2][3][4] = {
{
{1, 2, 3, 4},
{5, 6, 7, 8},
{9, 10, 11, 12}
},
{
{13, 14, 15, 16},
{17, 18, 19, 20},
{21, 22, 23, 24}
}
};
// Traversing the array
for (int i = 0; i < 2; i++) {
for (int j = 0; j < 3; j++) {
for (int k = 0; k < 4; k++) {
cout << arr[i][j][k] << ” “;
}
cout << endl;
}
cout << endl;
}
return 0;
}
In Python:
arr = [
[
[1, 2, 3, 4],
[5, 6, 7, 8],
[9, 10, 11, 12]
],
[
[13, 14, 15, 16],
[17, 18, 19, 20],
[21, 22, 23, 24]
]
]
# Traversing the array
for slab in arr:
for row in slab:
for element in row:
print(element, end=” “)
print()
print()
Summary
Arrays are fundamental data structures that store elements of the same type in contiguous memory locations. One-dimensional arrays represent a list of elements, while multi-dimensional arrays, such as two-dimensional arrays (matrices) and three-dimensional arrays, represent more complex structures like tables and cubes. Understanding how to declare, initialize, access, and traverse these arrays is essential for effective programming and data manipulation.