DEV Community: Kumar Sanskar

Program Control Statements 3

Kumar Sanskar — Fri, 28 May 2021 18:29:19 +0000

So it's day nine of my learning java journey and today I will discuss the topic of loops in program control statements.

Loops in general understanding means to repeatedly doing the same task over and over again for example writing Sorry hundred times to your professor for not submitting assignment on time😂😂.

Beware!

There are three general type of loop control structure in case of every programming language. They are -
i. For loop
ii. while loop
iii. do-while loop
but in java in addition to these we also have an enhanced for loop which is another variant of for loop which will be discussed after arrays so it is more understandable as per the book I am following.

for loop -

it is pretty easy in understanding and I suppose the syntax and example provoided will be self explanatory for it.
syntax -

   for(*intialization* ; *condition* ; *iteratation*)
   {
       statements
   }

example -

public class UsingForLoop {
    public static int NUMBER_ITERATIONS = 5;

    /*
     *here we demonstrate the of use the for loop for printing input name five times.
     */
    public static void main(String[] args) {
        System.out.println("Please enter your name: ");
        Scanner scannerObject = new Scanner(System.in);
        String studentName = scannerObject.next();

        for (int NUMBER_ITERATORS = 0; NUMBER_ITERATORS < 5; NUMBER_ITERATORS++) {
            System.out.println("Your name is: " + studentName);

        }
    }
}

it is also called as entry controlled loop because the condition is checked at the beginning of the loop and as soon as condition evaluates to 'false' the loop is terminated.
Infinite for loop -

   for(;;)
   {
     statements
    }

while loop -

it is a type of loop control structure where condition is checked in the beginning and loop executes or runs till the condition holds 'true'.
syntax -

     while(condition)
     {
       statements  
      }

example -

    public class UsingWhileLoop {
    /*
     *her ewe use while loop to print squares of number from 1 to 100.
     */
    public static void main(String[] args) {
        int i = 1;
        while (i <= 100) {
            System.out.println(i + "^2 =" + i * i);
            i++;
        }
    }
}

do while loop -

it is also a loop control structure but unlike for and while loop it is exit control in nature that is it will be executed at-least even when the condition is 'false'.
syntax -

   do{
    statements
   }while(condition);

exapmle -

public class usingDoWhileLoop {
    /*
     *here we use do while loop to add user input numbers till zero is input by user.
     */

    public static void main(String[] args) {
        int sum = 0;
        int number = 0;

        Scanner scannerObject = new Scanner(System.in);


        do {
            System.out.println("input a number: ");
            number = scannerObject.nextInt();
            sum += number;
        } while (number != 0);
        System.out.println("sum= " + sum);
    }
}

another type of program control structures apart form the loops are break and continue, they are statements and can even be used to alter the normal execution of program like break is used in switch statements.

That's the end of the program control structures although I left out the example for break and continue I will update it as soon as possible. Till then keep learning, keep growing and feel free to suggest any changes in post.

Program Control Statements 2

Kumar Sanskar — Thu, 27 May 2021 18:19:32 +0000

So today, is day nine of my learning Java journey and today I will discuss the another part of Program control statements in Java as said yesterday. So, let's get rolling.

Switch statements -

it can be said as a more enhanced as well as efficient version of if else condition as when there are multiple situations and pertaining to each of them there is a statement.
it works like as soon as a match to the condition is found then the statement related to it is executed and rest are discarded and if none then a default statement is executed.
also with each statement of by-conditions pertaining to an input break has to be used if break is not used then all statements will be executed.
*Syntax - *

   switch(expression){
       case constantOne:
       statement sequence
       break;
       case constantTwo:
       statementSequenceTwo
       break;
       .
       .
       .
       .
       default:
        statementSequenceDefault
}

here duplicate values are not allowed.
also the nesting can be implemented of switch case statements in Java just like the nesting of if-statements.
example -

public class usingSwitchCase {
    /*
     *here we enter a day number and by using switch case statement we return the corresponding day name.
     */
    public static void main(String[] args) {
        int dayNumber = 5;
        System.out.println("For day number "+ dayNumber +" from week the day name is: ");
        scanner.close();
        String dayName;
        switch (dayNumber) {
            case 1:
                dayName = "Sunday";
                break;
            case 2:
                dayName = "Monday";
                break;
            case 3:
                dayName = "Tuesday";
                break;
            case 4:
                dayName = "Wednesday";
                break;
            case 5:
                dayName = "Thursday";
                break;
            case 6:
                dayName = "Friday";
                break;
            case 7:
                dayName = "Saturday";
                break;
            default:
                dayName = "Invalid day number input.";
        }
        System.out.println("The day is " + dayName);
    }

}

Let's halt it here for the day today and will continue tomorrow from the next topic in program control structure that is loops.
Till then keep learning, keep growing. and feel free to point or add anything related to the topic that I may have missed.

Program Control Statements in Java

Kumar Sanskar — Wed, 26 May 2021 18:26:52 +0000

Hello readers, it has been a wonderful journey of learning Java till today and today is day eight of my learning Java. By now since you must have read the title of the post you must be aware that I must have studied Program Control statements today and so it is but since it contains a lot of topics I will be posting about them in parts.
Today I will discuss about the various if statements with their examples.

The if statement -

like we use the if in our normal English language in order to show and make use of the condition like for example - If Ram finishes his homework in time, his mother will reward him.

Here we show a condition that if Ram does his homework in time he would be rewarded so is the case with the if statements in Java programming it is used in programming to control the flow of program and decision making.

Syntax -

    if(condition)
    {
      statements
    }

example : -

public class UsingIfStatement {
    public static void main(String[] args) {
        // here we demonstrate using the if statement in a program.

        int numberOfBoys = 29;
        if (numberOfBoys == 29) {
            System.out.println("There are twenty-nine male students in the class.");
        }
        System.out.println("This statement is general statement and is independent of if block .");
    }
}

The if-else Statement -

it is similar to the 'if' statement discussed above but the only difference is that it contains an else so if the provided condition evaluates to false then other set of statements will be executed.
Syntax -

  if(condition)
    {
      statements
    }
  else(condition)
   {
      statements
   }

exapmle -


public class UsingIfElseStatement {
    /*
     * here we make a simple program which checks for the number to be even or odd using if else block.
     */
    public static void main(String[] args) {
        int checkNumber = 7;
        System.out.println("Check whether number 7 is even or odd? ");

        if (checkNumber % 2 == 0) {
            System.out.println("Number is even.");
        } else {
            System.out.println("Number is odd.");
        }
    }
}

Nested if Statements -

an if statement is said to be nested if statement when it is a result of another if statement in an if-else block
exapmle -

public class NestedIfStatements {
    /*in this program we learn how to use nested if statement in java
     *
     * here if first condition evaluates to true then second condition is checked to produce an output.
     */

    public static void main(String[] args) {
        int number1 = 4, number2 = -1;
        if (number1 > 10) {
            if (number2 > 0) {
                System.out.println("Number1 is = " + number1 + " and " + "Number2 is = " + number2);
            }
        }
        else{
            System.out.println("Sorry number1 and number2 didn't fall  in range of 10 and greater than 20.");
        }

    }
}

if else-if else ladder -

it is also like if and if else and nested if conditions but differs in a fact that as soon as condition evaluating to 'true' is found the statement related to it is executed and rest is discarded and if none of the conditions are evaluated as true then 'else' condition is executed. +

public class UsingIfElseifElseStatement {
    /*
     *here we check that whether a number is positive, negative or equal to zero.
     */
    public static void main(String[] args) {
        int checkNumber = 7;
        System.out.println("Check the number 7 whether it id positive, negative or zero. ");


        if (checkNumber > 0) {
            System.out.println("Number is Positive.");
        } else if (checkNumber < 0) {
            System.out.println("number is Negative.");
        } else {
            System.out.println("Number is zero.");
        }
    }
}

So, that's it for the day in program control statements tomorrow we will be discussing the other remaining topics in that, till then keep learning keep growing.
If you encounter any discrepancies feel free to point out or give any suggestions.

Operators in Java

Kumar Sanskar — Tue, 25 May 2021 18:29:39 +0000

Hello readers it's day seven of my learning Java journey and today I will share with you my learning of Operators in java.

As we have symbols in mathematics to perform certain calculation say the plus '+' for addition and so on similarly we have operators in Java to perform either a mathematical or logical manipulation

Java has four types of operators:- i. Mathematical ii. Logical iii. Relational iv. Bitwise

Mathematical Operators -

it contains all the symbols that are used in mathematical computation only just be a bit careful with the use of / and %.

Symbol	Function
+	addition
-	subtraction
*	multiplication
/	integer division (returns quotient)
%	modulus (returns remainder)
++	increment
--	decrement

the increment (++) and decrement (--) operators increase or decrease the value of operands by one.
it can be used in two ways either prefix or postfix.

Relational and Logical Operators -

relational and logical operators are used to show decide or compare two operands and they produce result as of type Boolean that is either true or false.
in case of logiacal operators the operands must be in form of boolean values.
- Relational Operataors:-

Symbol	Function
>	greater than
<	less than
>=	greater than equal to
<=	less than equal to
==	equal to
!=	not equal to

Logical Operators:-

Symbol	Function
&	AND

^	XOR

&&	SHORT-CIRCUIT AND
!	NOT

the difference between normal and short-circuit logical operators is that normal ones evaluate each operand but in case of short-circuit they only evaluate the second condition of necessary
the short-circuit operators are also known as conditional-and and conditional-or operators.

Assignment Operator -

it is used for assigning values to variables.
it is represented by normal '=' sign and should not be confused with '==' of relational operators.
java also allows you to make a chain of assignments that is to make them get a common value.
```
 int a, b, c;
 a = b = c =1;
```

Shorthand Assignment -

it is used to simplify the coding convention and save some time. for example-

  x = x + 10;
can be re-written as 
  x += 10;

Literals and Variables in Java.

Kumar Sanskar — Mon, 24 May 2021 18:28:20 +0000

Well I took a break of two days from my learning Java journey so that I could do my another favorite thing that is doing some art work after being surrounded from tech my all days, some time these breaks are necessary so as to give you a mental peace.
Enough of talks now let's get back to our business that is learning Java.

It's day six and today I will talk about Literals and variables.

Literals :-

literal can be anything that has a fixed value and can be represented in a human readable form and are also called as consonants.
in java literals can be of any of the eight primitive types.
in addition too the eight primitive types Java also supports Hexadecimal, octal, and binary literals.
Hexadecimal literals have to begin with 0x or 0X and octal literals have to begin with 0 and similarly binary literals have to begin with 0b or 0B.
Java furthermore also supports another type of literal String, it can be understood as set of characters enclosed by double quotes and can even contain character escape sequences like /n, /t etc.

Variables -

as evident from the name itself it refers to something that can vary and are used to declare as well as initialize values in a Java program.

Initializing Variables in Java

  type variableName = value;
  for example :- 
  int ageOfStudent = 20;

while declaring and initializing variables of same data type we can separate them using commas and even assign values simulatenously. for example -

    int ageOfStudent = 10, numberOfSiblings = 2;

java also supports dynamic initialization of variables that is at run time.
Scope and Lifetime of a Variable -
- in Java all the variables are defined within a block of code which like every other program is defined by opening and closing of curly braces.
- these blocks define a scope.
- in Java scopes are defined by two ways:-
  
  i. defined by methods
  ii. defined by class
a variable defined within a block is called local variable.
objects declared in outer scope will be visible to inner scope but the vice-versa will not hold true.

Closing here for the day, feel free to add, correct or suggest any mistake that may have crept in.

More into Data types!

Kumar Sanskar — Fri, 21 May 2021 18:28:15 +0000

Today is day five of my learning Java journey.

Yesterday, I had learnt and shared with you the data types available in Java and the various types under the respective Primitive and Reference data type. Today, I would be sharing more in depth about each of the data types discussed in the previous post.

As we had discussed that Java has eight sub types of data types under the category of Primitive data types.

The types Byte, Short Int and Long can be combined under one umbrella as Integer data types.

Type	Size in bits	Range
byte	8 bits	-127 to 128
short	16 bits	-32768 to 32767
int	32 bits	-2147483648 to 2147483647
long	64 bits	-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807

these types of integer data types have a wide implications from being as variable types in control statements, for example in loops as control variables data type to general purpose mathematics.
the byte and short data type are generally type-casted with (byte) or (short) so as to make it clear to compiler so as not to be mistaken with int.
also with large data type we use 'L' as format specifier. for example - 244368L
Another data type that combines two data types are Floating Point Types : -
- it consists of float and double.
- if you are new to programming let me break it clear for you that floating point numbers are those that have a decimal part in common language or technically those number which have a fractional component.

Type	Size in bits	Range
float	32 bits	1.4 E -45 to 3.402835E38
double	64 bits	1.7976931348623157 x 10308 to 4.9406564584124654 x 10-324

in case of data having float or double value we use format specifier 'f' or 'd' respectively. for example - 0.002f or 0.0235d.
- Char data type:-

Type	Size in bits	Range
char	unsigned 16 bits	0 to 65,535

also the ASCII values are valid as Java characters.
arithmetic manipulations are viable on char data type.
- Boolean data type:-
it has two values true and false.
these true and false are defined as reserved words in Java as it defines the values true and false using these words and not like in many programming languages where false is considered as 0(zero) and true as any other value than 0.

Closing for today, and will be sharing my next learnt topic tomorrow till then keep learning, keep growing. Also feel free to give any suggestions or add up any point that I may have missed.

Data types in Java

Kumar Sanskar — Thu, 20 May 2021 18:25:36 +0000

Another day in the journey of learning Java, well it's day 4 and today I will talk about the very essential component in any programming language 'data types', it can be thought as that important label without which we won't be able to identify the type of food kept in a container in kitchen.
Like every programming language, Java too has data types in order to facilitate the working on data and operations to be performed upon the data input by the user.
Java being a strongly typed language makes sure that all operations are checked for data type compatibility and illegal operations are rejected by the compiler. Furthermore the presence of data types makes it easier to determine what kind of operation are allowed on each type of data.

Java has two kinds of data types :-
1. Primitive Data type
2. Reference Data type
Primitive Data Types -
- they are also called the built-in data type.
- Java has eight types of data defined as primitive data types and they are:-
i. Byte
ii. Short
iii. Char
iv. Int
v. Long
vi. Float
vii. Double
viii. Boolean
Reference Data Type -
- it is also called as derived data type or non-primitive data type in Java.
- they refer to objects and are created by programmer.
- it has two subtypes :-
i. String, arrays, classes, intefaces.
ii. BigInteger,BigDecimal......and so on.

That's it for today my readers, see you in the next blog till then keep learning keep growing, also you can put any suggestion or remarks if you feel or point mistake that may have crept in.

Getting started with programming in Java

Kumar Sanskar — Wed, 19 May 2021 18:23:29 +0000

Well, it's day 3 of my learning Java journey and today we will move ahead in that by learning some components and how to write and compile our first program in Java.

In order to run and make programs in Java on your machine you needs to have something called as JDK which stands for Java Development Kit and can be installed from the respective website of oracle, you can also install its open sourced counter-part OpenJDK if you want to and YouTube as well as Google are always ready to help you in doing so, but with some advanced IDE's like IntelliJ you don't need to worry for that as they do it automatically.
JDK consists of :-
- JRE (Java Runtime Environment)
- JVM (Java Virtual Machine)
- Java Compiler(javac)
- Libraries
- Development tools.
JDK include JRE and other tool to develop and run programs.
JRE includes JVM and the standard libraries.
JVM executes the Byte-code.
Compilation Process of a Java Program:-
- this process is generally happens inside of JVM.

Source Code(*.java file) ----> given to javac compiler -----> Byte Code(.class file) -----> given to JVM ------->Native Machine code(binary code)

Now we come to final part of the blog that is writing and compiling our first Java program:-

//package information
package.codes.main;

//name of the class "Main" - executable class
public class Main{
    // name of the method "main" - executable method
    public static void main(String[] args){
        // statement to print out to console or display
        System.out.println("Hello, World!");
    }
}

I am assuming that with a prior knowledge of computer and IDE's everyone would be able to compile and check the output of the above program, also the line containing '//' are comments used to make it clear to a new person so as to make them understand what each line does in this program and won't be visible in the output.

Let's catch up in another post tomorrow, till then keep learning keep growing also do let me know of any suggestion and improvements in the comments below.

Main features that made Java it is today!

Kumar Sanskar — Tue, 18 May 2021 18:24:06 +0000

Hey there so it's day 3 of the learning journey and as in my previous post, I mentioned some of the features of Java while closing that post. In this, we are gonna take some of those features that made Java as we know it today.

1.Object-oriented -

at the heart of Java is this paradigm that made it one of the most sought after programming languages in the list of programmers and developers.
as we all know, before the advent of Java and this paradigm of programming, mostly all the programs were structured in nature. With time, they exceeded that approach where the structured programming was no longer useful.
in the object-oriented approach the programs are organized around data that is we make it clear in our program that how that data is defined and what changes and modifications can be made to that data and it follows somewhat is close to real-life hierarchies.
it is based on the concept of the objects.
contains data in the form of fields also called attributes or properties
contains code in the form of procedures also known as methods.
methods of an object with fields and objects interact with other objects.
this object-oriented model had three major traits that got adopted by Java namely encapsulation, polymorphism and inheritance and became a major part.

2.Encapsulation -

encapsulation in a general sense means to inclose something within a capsule and similarly, it is with the object-oriented model and Java.
it is a way to bind our code and data on which it operates in such a way that their misuse can be reduced by external factors.
in Java basic unit of encapsulation is a class, as we said that object are instances of a class so conversely, we can take from that class can be thought as a set of rules specifying how to build that object and while creating those objects we can make sure which other classes can modify and make alterations to the object which we have created in a class.

3.Polymorphism -

polymorphism has originated from Greek words 'poly' meaning many and 'morphe' meaning forms, that is to perform a single task with different inputs you don't need to repeatedly make structures to perform that task all you need is to define a general structure for how that task is to be performed.
for Java generally the polymorphism is expressed by the phrase " one interface, multiple methods".

4.Inheritence -

we all must have heard this word in our biology classes haven't we and you can say this concept of object-oriented paradigm was taken from there, in biology inheritance means passing down certain genetic traits from parents to their offsprings.
in the case of Java and object-oriented programming it can be understood as the process by which one object can acquire the properties of another object, as we know that the object-oriented paradigm is based on hierarchical classification this feature furthermore supports that; an object will just need to define those qualities that make it unique within its class it's other properties that are preceded by its preceding class can be accessed and reused by using this feature of inheritance.

Closing for the day, I will like to hear from your side my readers too for any improvements or suggestions.

Some basic terminologies in Java

Kumar Sanskar — Mon, 17 May 2021 17:00:17 +0000

So it's day 2 of the learning journey and today we will get to know some of the basic terminologies used frequently in java.

Classes -
- classes can be identified as Nouns in the problem statement
- they are also called the blueprint of an object.
- as per the rule every single class should define the single object and should contain data related to that object only.
- For example - A human
Objects -
- also called as an instance of the class.
- consists of the exact values of the fields/properties defined by a class
- objects are always related to the class.
- For example - If humans are class then John is one of its objects.
Fields -
- fields can be of both objects as well as classes they are also called attributes or property.
- they define actual values that an object of a class can hold.
- only a method of an object should be allowed to change values of a field of the same object.
Methods -
- it can also be of both classes and objects.
- can be understood as behaviours of an object or procedures.
- are functions associated with an object.
- changes values of fields of an object.
Naming Convention in Java:-
- PascalCase => used for naming Class.
- camelCase => used for naming Fields, Methods.
- SCREAM_CASE => used for naming Constant Values.
- lowercase => used for naming packages.
Some key features of Java:-

i. Object-Oriented
ii. Platform Independent
iii. Simple and Easy to learn
iv. Architecture Neutral
v. Portable
vi. Robust
vii. Multi-threaded
viii. Interpreted-byte code
ix. High performance
x. Distributed
xi. Dynamic

Why take up Java as a programming language?

Kumar Sanskar — Sat, 15 May 2021 18:33:47 +0000

Okay, so Day 1 of my learning journey and as I said that I will be sharing the journey details of my learning Java, so without any delay let's roll in.
Like every new learner, I was quite apprehensive of me choosing Java as a primary programming language as we all know that with the talks of other programming languages like Python and others rounds the corner the task of selecting a language becomes quite hard. But let me tell you why should you chose Java:-

What if I tell you that about 13 Billion devices run Java and that's a really huge number isn't it, from the smartphones to the smart chips in credit cards, to server-side process and lot many more.
Another amazing fact that it has been in use for almost two decades now, as Java 1.0 came out in 1995 and that's a pretty good share of time for a programming language where after few years there is a new language in the market and another departs from the market.
Now there will be an obvious question that how did it survive through time and the reason is by having backwards compatibility which is also one of the features of Java.
It has a huge community of developers about 10 million from all around the globe and that makes it a lot easier for you if you feel stuck somewhere and obviously if you are looking for help on StackOverflow😅.
It was mainly derived from C and C++ and you can say they are the nearest ancestor of Java, as it's quite evident that from C Java derives many of its syntaxes and from C++ it's Object-oriented model.
But be careful there are some instances where using Java can be Dangerous like for the systems which are using real-time systems(basically because of garbage collection) apart from some of the places like this it is one of the best choices as a programming language

"When web companies grow up, they turn into Java shops." - James Governor(Redmonk analyst and co-founder)

So Java, it is.

Kumar Sanskar — Fri, 14 May 2021 18:48:47 +0000

Since this is my first post or rather a small blog introducing myself and why the post has such an unusual heading let me make it easier for you.
So if you go through my profile on this platform, you see that I have mentioned that I am currently pursuing my Bachelors from G.L.A. University, Mathura in Computer Science and Engineering and during the course I have now decided to finally pick Java as my fundamental programming language.
And guess what! I decided that I will be sharing my journey and the path taken to achieve my goal.
I would be making it like a journal where every day I will be briefing about the topic that I learnt, and the resources I would use.
Let's see how much this approach of learning works for me, keeping the finger crossed🤞 for the best.