Question

hi, I'm a new student of c++, I found it's difficult to understand the class, can you guys please give me an example of how to create a two dimensional array in a class. like create an array[3][4] in a class, let the user input the value of array. Thank you.

Answer 1

Definition - Array:

• An array is a data structure that is used to store the fixed size of sequential collection of data.
• An array stores the elements of same datatype.

Advantage:

• If a user or customer needs to store 100 elements of type integer, it is very difficult to create 100 variables which results in time and space complexities.
• To store these collection of elements of same data type we use arrays.

Declaring an array in c++:

  int balance[5];

int   - integer data type

balance - array name

5   - size of the array

2 dimensional Array:

Syntax: data_type array_name [size1][size2];

example:

int balance[4][3];

The above example creates an array with 4*3 = 12 elements.

Here 4 denotes the number of rows

3 denotes the number of columns.

Description:

• A 2 dimensional array is similar to matrix of m rows and n columns.
• It can be represented as tabular format.
• An array with 2 rows and 3 columns are represented as

	Column 0	column 1	column 2
Row 0	Array[0][0]	Array[0][1]	Array[0][2]
Row 1	Array[1][0]	Array[1][1]	Array[1][2]

C++ program for 2 dimensional array:

#include <iostream>

using namespace std;
class TwoDimensional
{
public: //access specifier
void createArray()
{
int row, col; //varibale declaration
cout << "Please enter the rows size: " << endl; //message displayed to user.
cin >> row; //to read data(number of rows) from user
cout << "Please enter the column size: " << endl;
cin >> col; //to read data(number of columns) from user

cout << "Please enter the numbers you want to put into a 2D array" << endl;
cout << "Press enter after each number you input: " << endl;

int arr[row][col]; //2 dimensional array declaration
//for loop to read the 2 dimensional array from user
for (int i = 0; i < row; ++i) {
for (int j = 0; j < col; j++) {
cin >> arr[i][j];
}
}
  
//for loop To print the array
for(int i=0;i<row;i++) {
for(int j=0;j<col;j++) {
cout << arr[i][j] << " ";
}
cout << endl;
}
cout << endl;
}
};

int main()
{
TwoDimensional td; //To create an object(td) for the class TwoDimensional
td.createArray(); //function call to createArray
return 0;
}

Output:

Please enter the rows size: Please enter the column size: Please enter the numbers you want to put into a 2D array Press enter after each number you input: به هر نا 1 2 34 ... Program finished with exit code o Press ENTER to exit console.U