Two Dimensional Array in C++

# Two Dimensional Array in C++ - Basics of C++ - Software Development

 Table of contents What is an Array? What is a Two-Dimensional Array? Declaring a Two-Dimensional Array Iterating Over a Two-Dimensional Array Conclusion

## What is an Array?

An array is a collection of elements of the same data type, stored in contiguous memory locations. It provides a convenient way to store and access multiple values using a single variable.

## What is a Two-Dimensional Array?

A two-dimensional array is an array in which elements are arranged in a two-dimensional grid or matrix. It can be visualized as a table with rows and columns. This data structure is useful when working with grids, matrices, tables, and other similar structures.

## Declaring a Two-Dimensional Array

To declare a two-dimensional array in C++, you specify the data type of the elements and the dimensions of the array. The syntax for declaring a two-dimensional array is as follows:

dataType arrayName[rowSize][columnSize];

Here, 'dataType' is the type of elements in the array, 'arrayName' is the name of the array, 'rowSize' specifies the number of rows, and 'columnSize' specifies the number of columns.

Example: Declaring a Two-Dimensional Array

Let's declare a two-dimensional integer array named 'matrix' with 3 rows and 4 columns:

int matrix[3][4];

### Accessing Elements in a Two-Dimensional Array

To access an element in a two-dimensional array, you use the row and column indices. The indices start from 0 and go up to the size of the array minus 1.

Example: Accessing Elements in a Two-Dimensional Array

int matrix[3][4];

// Assigning values to elements

matrix[0][0] = 1;

matrix[0][1] = 2;

matrix[0][2] = 3;

matrix[0][3] = 4;

matrix[1][0] = 5;

matrix[1][1] = 6;

matrix[1][2] = 7;

matrix[1][3] = 8;

matrix[2][0] = 9;

matrix[2][1] = 10;

matrix[2][2] = 11;

matrix[2][3] = 12;

// Accessing elements

cout << matrix[0][0];  // Output: 1

cout << matrix[1][2];  // Output: 7

### Initializing a Two-Dimensional Array

You can initialize a two-dimensional array at the time of declaration using an initializer list. The number of elements in the initializer list should match the size of the array.

Example: Initializing a Two-Dimensional Array

int matrix[2][3] = {

{1, 2, 3},

{4, 5, 6}

};

## Iterating Over a Two-Dimensional Array

You can use nested loops to iterate over the elements of a two-dimensional array. The outer loop controls the rows, and the inner loop controls the columns.

Example: Iterating Over a Two-Dimensional Array

int matrix[3][3] = {

{1, 2, 3},

{4, 5, 6},

{7, 8, 9}

};

// Printing elements

for (int i = 0; i < 3; i++) {

for (int j = 0; j < 3; j++) {

cout << matrix[i][j] << " ";

}

cout << endl;

}

1 2 3

4 5 6

7 8 9

### Sample Problems

Problem 1: Write a C++ program to find the sum of all elements in a given 3x3 matrix.

#include <iostream>

using namespace std;

int main() {

int matrix[3][3] = {

{1, 2, 3},

{4, 5, 6},

{7, 8, 9}

};

int sum = 0;

for (int i = 0; i < 3; i++) {

for (int j = 0; j < 3; j++) {

sum += matrix[i][j];

}

}

cout << "Sum of elements: " << sum << endl;

return 0;

}

### Output

Sum of elements: 45

Problem 2: Write a C++ program to find the maximum element in a given 4x4 matrix.

#include <iostream>

using namespace std;

int main() {

int matrix[4][4] = {

{3, 7, 2, 9},

{4, 1, 8, 5},

{6, 2, 4, 7},

{9, 3, 5, 1}

};

int maxElement = matrix[0][0];

for (int i = 0; i < 4; i++) {

for (int j = 0; j < 4; j++) {

if (matrix[i][j] > maxElement) {

maxElement = matrix[i][j];

}

}

}

cout << "Maximum element: " << maxElement << endl;

return 0;

}

### Output

Maximum element: 9

## Conclusion

In this article, we covered the basics of two-dimensional arrays in C++. We learned how to declare, access, initialize, and iterate over two-dimensional arrays. Two-dimensional arrays are a powerful tool for handling structured data in programming. By understanding and practicing with them, you'll be well-equipped to work with grids, matrices, and tables in your C++ programs.

The document Two Dimensional Array in C++ | Basics of C++ - Software Development is a part of the Software Development Course Basics of C++.
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## Basics of C++

70 videos|45 docs|15 tests

## Basics of C++

70 videos|45 docs|15 tests

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