Core Java(Part-4)

Content

.Operators

.new

.Conditionals loop

Operators

Operator is a symbols in java which tells to compiler to perform some operations. Operator is used to perform operations between operands.

Assignment operator

Assignment operator used to assign value to the operand

eg:- int a=10;//in a variable store the value 10

Comparison operator

Comparison operator used to compare the values, operand. It gives only output in the boolean format(true/false).

Logical operator

Logical Operators = Java ka dimaag (brain) for TRUE or FALSE thinking.
They help Java decide stuff like:
“Should I do this?”
“Are BOTH conditions true?”
“Is at least ONE true?”
“Is it NOT true?”

&&

AND

“Both things must be true, bro!” ✅✅

||</p></td><td colspan="1" rowspan="1"><p></p></td><td colspan="1" rowspan="1"><p>”Only one must be true bro!” ❌✅

!

NOT

“Flip it! True becomes false, false becomes true” 🔄

Logical operator is also used perform operation between operands. It also gives output in the boolean form(true/false) In it there are 2 operator &&(AND), ||(OR)

In AND(&&) operator if all condition is true only then it gives true output, if even a single one gives false output then the whole output becomes false

eg:-(4>2 && 2>1 && 3>4)=>false

it gives false output because first two condition is true but the last one is false, so it gives the output false.

In OR( || ) operator it just opposite of AND operator in it if even a single one is true then it give the true output.

eg:- (4>2 || 2>1 || 3>4)=>true

In NOT(!)

When you toss the coin and you get head then it becomes tails and in next time when you flip and then you get tail then it becomes head. In it NOT operator just give the opposite of the answer you get(true becomes false, false becomes true)

Unary operator

It is used only in single operand. It works on just one value — like a solo player doing all the action alone.

You have a glass of water. You can either:

• Fill more water = ++

• Drink some = --

• Check if it's empty (true/false) = !

That’s unary operators in action —Ek hi cheez par kaam karta hai.

Ternary operator

It's Java's shortcut for an if-else statement.
Like saying:
“Bro, don’t write 5 lines… just say it in 1 line!”

condition ? value_if_true : value_if_false;

"If this is true? Do this : Otherwise, do that"

Java be like:

• “Are you hungry?”

• If yes,

• If no,

int age = 18;

String result = (age >= 18) ? "You can vote" : "Too young, bro!"; 
System.out.println(result);//

output:you can vote

new

1.new is a java keyword which is used to create object.

2.We can create object for predefined or user defined class.

3.creating an object is nothing but allocating the memory so that we can use in the application.

4.Once an object is created then object will be allocated in the heap memory.

Imagine you’re in a toy factory

• You have a blueprint of a teddy bear (called a class)

• But you want to make an actual teddy to hug

• eg:-

• Teddy myTeddy = new Teddy();

Program

//Declaration of class

class Teddy{

    int height=10;

    public void teddy{

        System.out.println(height);

    }

    Teddy myTeddy=new Teddy();

}

What does new keyword do

• It allocates memory for the object

• Calls the constructor of the class

• And gives you a fresh, usable object

. Operator

Dot (.) = Java ka “access karne wala remote control”

It lets you access stuff inside an object, class, or package.

Where does we use (.) dot operator

Prog:

import java.util.Scanner;

public class Car{

    String color=”Red”;

    public void start(){

        System.out.println(“Car Start”);

    }

    public static void main(String args[]){

        Car car = new Car();

        car.color;

        car.start();

    }

Access method

car.start()

Tell the car to start

Access variable

car.color

Ask car what color it is

Access package/class

java.util.Scanner

Find Scanner inside util inside java

Conditionals

1. Conditionals (aka If-Else Wale Faisle)

Java be like: "Check karo… phir decide karo kya karna hai."

🍔 Lame Analogy:

You're at a momo shop.

javaCopyEditif (money >= 50) {
    buyMomos();
} else {
    cryInCorner();
}

Java be like: “Paise hain? Toh momos ✅ Nahi? Toh rona ❌”
That’s if-else logic — “check condition, take action” 🎮

✅ Types:

• if → check one condition

• if-else → choose between two

• else if → multiple options

• switch → like a menu card 🍽️: pick something from many choices

2. Loops (aka Kaam baar-baar karne ki machine)

Java be like: "Jab tak bolta hai, main repeat karta rahunga!"

Lame Analogy:

You’re eating fries one by one from a big packet.

javaCopyEditwhile (friesLeft) {
    eatFries();
}

Java be like:

“Fries khatam nahi hue? Toh khate raho! ”

🔁 Types of Loops:

Loop Type	Lame Meaning
while	“Jab tak condition true hai, chalte raho” 🏃‍♂️
do-while	“Pehle ek baar karo, fir check karo” 😏
for	“Mujhe batao kitni baar repeat karna hai” 🧾

for (int i = 1; i <= 5; i++) {

        System.out.println("Hi " + i);

}

Conditionals = Java ka dimaag ("soch ke faisla lo")
Loops = Java ka stamina ("jab tak bolta hai, karta rahu")