Array Creation and Access
Learn how to create an array and access data from it, in Java.
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Let’s build an easy scenario before moving any further. Suppose a teacher has to grade papers in total. As a programmer, you don’t want to make five different variables for it. Let’s get this done with arrays.
Create an array
Look at the code below.
class CreateArray{public static void main(String args[]){int[] marks = {100, 87, 93, 76, 45}; // Creating an array}}
We take marks as integers. Look at line 5. Let’s go through it:
int: Type of the values you want in an array[]: Square brackets right after the typemarks: Name of the array variable
Up until now, the array marks have been declared. In the other part, we add the values. Values are added within {} (curly braces). Note: we add five values, as discussed above, when building the scenario.
⚙️ Note: Arrays can store either primitive data (like
int) or object reference data (likeStringsor a custom class).
The new keyword
What if, we don’t want to add values at the time of creation? For this, Java has a keyword: new. Let’s modify the program above.
class CreateArray{public static void main(String args[]){int[] marks = new int[5]; // Creating array with 'new' keyword}}
The size of an array is established at the time of creation and cannot be changed.
Access elements of an array
Square brackets ([ ]) are used to access and modify an element in an array using an index. Look at the program below.
class AcessArray{public static void main(String args[]){int[] marks = {100, 87, 93, 76, 45}; // Creating an arraySystem.out.println(marks[0]); // Acessing an element}}
Initially, we make an array of five elements. Look at line 6. We print marks[0].
It prints the value at th index (first value): ...