class Array_TechSarvam
{
public static void main(String args[])
{
// Declaration and instantiation
int a[] = new int[5];
// Initialization
a[0] = 10;
a[1] = 20;
a[2] = 70;
a[3] = 40;
a[4] = 50;
// Printing array elements
for (int i = 0; i < a.length; i++) // length is the property of array
{
System.out.println(a[i]);
}
}
}
Step-by-Step Explanation of the Program:
Let’s get more up close and personal with this line by line code.
1. Declaration and Instantiation of Array
Int a[] = new int[5];
The declaration is making an array named a of type int that stores 5 integers.
new int[5] instantiates a new array of five elements, and all the elements are initially assigned 0: that is, the default initial value for int arrays in Java.
In this step, the array a becomes:
[0, 0, 0, 0, 0]
2. Array Initialization:
a[0] = 10;
a[1] = 20;
a[2] = 70;
a[3] = 40;
a[4] = 50;
Each of the elements of the array is assigned a value. Precisely
a[0] is taken 10.
a[1] is taken 20.
a[2] is taken 70.
a[3] is taken 40.
a[4] = 50;
As soon as it is done the array a has the form of:
[10, 20, 70, 40, 50]
3. Displaying Elements in an Array
for (int i = 0; i < a.length; i++) {
System.out.println(a[i]);
}
- The for loop in order to process the elements from the array.
- a.length is the field that prints the length of the array (in this case, 5).
- The for loop will run from i = 0 to i = 4inclusive; that is, it will iterate over all 5 elements of the array.
- System.out.println(a[i]); prints every single element of the array to the console, one at a time.
Output:
10
20
70
40
50
Key Concepts:
1. Array Declaration and Instantiation:
int a[] = new int[5]; declares an array a of type int and size 5. This provides memory for five integer elements.
2. Array Indexing:
Java arrays are 0-indexed. This implies that the first element is located at a[0], the second at a[1], and continues to a[4].
3. Array Length:
a.length returns the number of elements in the array (in this case, 5). It is an array property in Java.
4. For Loop for Iteration:
The for loop iterates over the array by using the index of the array. It begins at index 0 and goes up to a.length – 1, which is the last valid index of the array.
5. Array Initialization:
Array elements are initialized individually by specifying the index (a[0], a[1], etc.) and assigning a value.
Conclusion:
This program demonstrates the declaration, initialization, and traversal of an array in Java. It uses a simple for loop to iterate over the elements of the array and print them to the console.