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luthfisauqi17
luthfisauqi17

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Simple Way to Print Array in Java

#programming #beginners #java #tutorial

Back in the days when I first learned arrays in the Java programming language, I was very impressed with the visualization of arrays on the internet like the following example...

Visualization of an array

..so I want such array visualization to appear in my output to make it easier for me to debug if something goes wrong in my program.

Can you guess what I did?

Yes, I'm trying to print the object array as you can see in Source code 1.

Source code 1:

int[] arr = {1, 2, 3, 4, 5};

System.out.println(arr);
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Which will produce the following output...

Output 1:

[I@24d46ca6
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Then I realized that if we try to print an object in Java, the memory location of the object will be printed.

Then I thought, I have to implement the code for my own array visualization to be able to achieve the result I want.

Therefore, I decided to implement the code as you can see in Source code 2.

Source code 2:

int[] arr = {1, 2, 3, 4, 5};

System.out.print("[");
for (int i = 0; i < arr.length; i++) {
    if(i == arr.length-1)
        System.out.print(arr[i]);
    else
        System.out.print(arr[i] + ", ");
}
System.out.println("]");
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It was a success, because my code was able to print the array as I wanted it to look like in Output 2.

Output 2:

[1, 2, 3, 4, 5]
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After reading the documentation for the Arrays class in Java, I know that there is one method that can be used to print an array. The method is .toString(), and it takes one parameter as you can see in Syntax 1.

Syntax 1:
public static String toString(int[] a)

  • a is the array.

Source code 3 is the implementation of this method.

Source code 3:

int[] arr = {1, 2, 3, 4, 5};

System.out.println(Arrays.toString(arr));
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And with far fewer lines of code, the implementation of this method has the same result as Source code 2.

Output 3:

[1, 2, 3, 4, 5]
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So, if you are trying to print an array with a good look, you can use the toString() method which comes from the Arrays class. And also a note, although in this article I use array of integers as the example, but this method can also take arguments with various datatypes such as short, boolean, etc.

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