Suppose
if we want to represent our record in the form of table, then we always think
what we can do to represent our record in the form of table which consists of rows
and columns. Then array plays a vital role. Here to overcome with this problem
we will use 2D array which consists of multiple rows and columns. Syntax –
int num[][]
= new int[][];
int
num[][]={{1,2,3,4},{4,5,6,7}};
Let us
take an example –
int a[]
={1,2,3};
int
b[]={3,4,5}
int
c[]={4,5,7}
Now
suppose if we want to store the values of all the above array in one array then
the structure would be something like this –
int d[][] = {
{1,2,3},
{3,4,5},
{4,5,7}
}
Where the
elements are represented in the form of rows and columns. So the first row
first value will be in the position 0th row and 0th
column, second element will be 0th row and 1st column and
so on. For the second row the first value will be in the position 1st
row and 0th column, second value will in position 1st row
and 1st column.
Now how
to work with this kind of an array then we have to take two loops where the
first loop will count for the number of rows and the second loop will keep
track for columns.
Example –
public class
Array6 {
public static void
main(String[] args) {
int num[][]={
{1,2,3},
{3,4,5},
{4,5,7}
};
for(int i=0;i<num.length;i++)
{
for(int j=0;j<num.length;j++)
{
System.out.print(num[i][j]+" ");
}
System.out.println();
}
}
}
Output –
1 2 3
3 4 5
4 5 7
Example –
import
java.util.Scanner;
public class
Array7 {
public static void
main(String[] args) {
Scanner sc
= new Scanner(System.in);
int num[][]=new int[3][4];
System.out.println("Enter values in 2D array");
// assigning values to 2D array
for(int i=0;i<num.length;i++)
{
for(int j=0;j<num.length;j++)
{
num[i][j]=sc.nextInt();
}
}
//fetching the values
System.out.println("Fetched records are");
for(int i=0;i<num.length;i++)
{
for(int j=0;j<num.length;j++)
{
System.out.print(num[i][j]+" ");
}
System.out.println();
}
}
}
Output –
Enter values in 2D array
1
2
3
4
5
6
7
8
9
Fetched records are
1 2 3
4 5 6
7 8 9
Example –
import
java.util.Scanner;
public class
Array8 {
public static void
main(String[] args) {
Scanner sc
= new Scanner(System.in);
System.out.print("Enter number of rows : ");
int row
= sc.nextInt();
System.out.print("Enter number of columns : ");
int col
= sc.nextInt();
int num[][]=new int[row][col];
System.out.println("Enter values in 2D array");
// assigning values to 2D array
for(int i=0;i<num.length;i++)
{
for(int j=0;j<num.length;j++)
{
num[i][j]=sc.nextInt();
}
}
//fetching the values
System.out.println("Fetched records are");
for(int i=0;i<num.length;i++)
{
for(int j=0;j<num.length;j++)
{
System.out.print(num[i][j]+" ");
}
System.out.println();
}
}
}
Output –
Enter number of rows : 3
Enter number of columns : 3
Enter values in 2D array
1
2
3
4
5
6
7
8
9
Fetched records are
1 2 3
4 5 6
7 8 9
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