My Easy Tuts

Simplified Coding Lessons

Abstraction in Java with Example – Easy Detailed Guide

Abstraction is an important concept of OOPs. It mainly focuses on the security of a program or application that you are developing.

Abstraction-in-java

What is Abstraction?

We use this term in general day to day life as well. Abstraction means hiding irrelevant things and showing them only the things that matters the most. In programming, we use Abstraction to hide the implementation of the internal code due to security and show only the relevant method to the user.

Example of Abstraction

Ex -1:- Let’s say you are playing the video game. While playing the game, you can operate the game using a few buttons on your console. Each of those buttons performs some action in the game.
While writing code for a video game, we don’t show the internal working or implementation of the game. We provide user highest level of abstraction by which he can only operate the whole game using few keys.

Ex -2:- In Real software projects, we use abstraction heavily in our code. Let’s say we want to make API calls to get some data from our server. For that purpose, we will write create an internal abstraction in our code. So, that every time, when we need to make an API call. We just have to pass fewer details and we will receive output based on that.

Also, Read – Guard Statement in Swift 5

How to achieve Abstraction in Java?

We can achieve Java Abstraction using Interfaces and Abstract Classes. Both of them have slightly different use cases.
Data Abstraction in Java

  • Interfaces – By using Interfaces, we can achieve full abstraction in our project.
  • Abstract Classes and Methods – By using Abstract Classes and methods, we can achieve partial abstraction which is needed in many cases as well.

Java Abstraction using Abstract Methods and Classes

In Java, Abstract modifier is applicable only for classes and Methods. We can’t use this modifier on Variables.

public abstract class StudentDetails{
	private String name;
	private int studentId;

	public void publicDetails(){
		System.out.println("Student Name is " + name)
		System.out.println("Student ID is "+studentId)
	}

	public abstract void personalDetails(Int mobileNo, String bloodGroup);
}

public class AdmissionDep extends StudentDetails{
	private int mobileNo;
	private String bloodGroup;

	@Override
	public void personalDetails(Int mobileNo, String bloodGroup){
		this.mobileNo = mobileNo;
		this.bloodGroup = bloodGroup;
		System.out.println("Mobile no is "+ mobileNo);
		System.out.println("Blood Group is "+ bloodGroup);
	}
}

In the above Java Abstraction Code example, we used an Abstract class StudentDetails. We inherited that StudentDetails class to AdmissionDep class.

When we inherit an Abstract class, it is mandatory to define each of the abstract methods in the parent class. In our code, we defined the personalDetails method in it.

CoreData error: Failed to call designated initializer on NSManagedObject class

When you will get this error?

It’s a very common error who just started using Core Data in their iOS development journey. It comes when you create an instance of the Core Data class. e.g.
var items = Item() //Here Item is a Core Data class.

Reason for this error

In Core Data, Creating a direct instance of the Class is not allowed. We must use the designated initializer. e.g.
Item(context: NSManagedObjectContext)
or
Item(entity: NSEntityDescription, insertInto: NSManagedObjectContext?)

Solution for this error

Don’t create a direct instance of the Core Data Class.
1) Create an instance using the designated initializer
OR
2) Create an Optional type, if you are not using the object right away.
var item : [Item]()

Solved – The local repository is out of date – Xcode

When you will get this error?

This is a very common error in Xcode. It comes when the user tries to commit and push the changes into a git branch.

The local repository is out of date

Reason for this error

Xcode shows this error when your online repository has some updates files than the current version on your system.
In other words, your repository is updated by someone. Generally when we add, Readme.md file on GitHub, we commit it using the site itself. This causes the updation on the online repository. But it is not updated on your local machine.


Solution for this error

To avoid this error, we need to pull the updated repository and then only we can commit the new changes. So, to solve it
– pull the updated repository
– merge your code (The updated code you wrote on your machine)
– Commit and push again

Python Program to Calculate Number of Digits in an Integer

Ques – Accept an integer value from the user and calculate the number of digits in provided value. e.g. 679 has 3 digits

Calculate the number of Digits in an Integer using Python

number = int(input('Enter a number '))
length = 0

while number/10 >= 1:
	number //= 10
	length+=1

length+=1

print('There are {} number of digits in the provided integer.'.format(length))

 

Explanation of Program to calculate the number of Digits in Python

  • In the first line, we are using input() function and accepting the input from the user. After that, we are type casting it to an integer value.
  • In the second line, we are declaring an integer variable length and set its value to 0. We will use this variable to store the final output of our answer.
  • In the fourth line, we are using the while loop in our program. This loop will iterate until the original integer is greater than or equal to 1.
  • In the fifth line, we are using floor division operator to reduce the value by 10.
  • In the sixth line, we are incrementing the length.
  • In the eighth line, we are incrementing the length again, because if we passed single digit integer, then it will never go to the while loop. So in that case, we have to increment the length variable here too.
  • In the last line, we are printing the output on the console.

Python Program to Add Two Numbers – My Easy Tuts

We need to accept input from the user on Console and provide the result after adding the two numbers. The problem is very straightforward and easy too.

Python code to add two Numbers

num1 = int (input('Enter First Number '))
num2 = int (input('Enter Second Number '))
print('The Sum is {}'.format(num1 + num2))

Explanation of python addition code

  1. In the first line, we are using input function and displaying the message “Enter First Number” in it.
  2. By default, input function will store the data as String type. We need to convert it into integer data type by typecasting it. So, we are using (int) for it.
  3. In the second line, we repeated the above steps again to store the second integer value.
  4. In the third line, we are using print() function to display the output on the console. Instead of storing the value into the third variable. We are directly adding the two numbers while formatting the String.
  5. In the print functions, {} is the placeholder. By mentioning it, we are telling the python to print the result over there.
  6. .format(num1 + num2) is used for addition of two numbers and place the result on the String.

 

Python Single Line Code to add Two Numbers

print('Answer is {}'.format((int(input('Enter first Number ')))+(int(input('Enter Second Number ')))))

 

Explanation of the Code

In this code, we are nesting two functions. We are using input() function of Python inside print() function. Basically while formatting the String, we are asking for the values from the user. After that, we are typecasting it to Integer. Then after adding the two values, we are printing the result on the console.