Arrays in Java
Arrays are used to store a set of similar data's of same data type.
Imagine if want to store five roll numbers in a Java program. What you will do ?
You will declare variables for every roll numbers separately like rollno1, rollno2. Right ?
Suppose imagine if you need 500 roll numbers to be stored.
We should write many lines of code or statements. To avoid this, we can use arrays.
To declare a array
datatype array_name[]=new datatype[array_size];
To initialize a array
array_name[index]=value;
We can also combine declaration and initialization as above,
datatype array_name={value1,value2};
Example
public class Arrays {
public static void main(String args[]) {
int rollno[]=new int[2];
rollno[0]=1;
rollno[1]=2;
}
}
Try In CompilerArrays can be 1D, 2D, 3D based on the application requirements.
The above is 1D array, For 2D arrays we can use datatype variable_name[][]=new variable_name[][];. Similarly for 3D, 4D we an use additional square boxes.
Index of a array variable starts from 0 to size-1 i.e rollno[0] to rollno[size-1] in above example.
We can use any datatype whenever needed.