











Introduction to 2-D Arrays in C++


Introduction to 2-D Arrays
Multidimensional Arrays can be defined in simple words as an array of arrays. Data in multidimensional arrays are stored in tabular form (in row-major order).
The 2D array is organized as matrices which can be represented as the collection of rows and columns.
Syntax :
The syntax of declaring a two-dimensional array is very much similar to that of a one-dimensional array, given as follows.
datatype variable_name[rows][column];
How do we access data in a 2D array
The elements of 2D arrays can be randomly accessed. Similar to one-dimensional arrays, we can access the individual cells in a 2D array by using the indices of the cells. There are two indices attached to a particular cell, one is its row number while the other is its column number.
we can store the value stored in any particular cell of a 2D array to some variable a by using the following syntax.
int x = a[i][j]
where i is row index and j is column index .


Size of 2-D array
The total number of elements that can be stored in a multidimensional array can be calculated by multiplying the size of all the dimensions.
Example: The array int a[5][6] can store total (5*6) = 30 elements.
Initializing 2D Arrays
DIRECT METHOD
data_type[][] variable_name = { {R1C1, R1C2, ….}, {R2C1,R2C2, ….} };
Example: int [ ][ ] arr = { { 2 , 4 } , {6, 8 } };
USING LOOPS
We can use loops for initializing 2d array like
for (int i = 0; i < 2; i++) { for (int j = 0; j < 2; j++) { int a = x[i][j]; } }
C++ Code to show how to initialize and print 2-D array
#include<stdio.h> using namespace std; int main() { // an array with 3 rows and 2 columns. int x[2][3] = {{1,2,3}, {4,5,6}}; // output each array element's value for (int i = 0; i < 2; i++) { for (int j = 0; j < 3; j++) { cout << "Element at x[" << i << "][" << j << "]: "; cout << a[i][j]<<endl; } } return 0; }
Output :
Element at x[0][0]: 1 Element at x[0][1]: 2 Element at x[0][2]: 3 Element at x[1][0]: 4 Element at x[1][1]: 5 Element at x[1][2]: 6
Login/Signup to comment