Remember in array

1. This if you still don't know the values

double[] the_salaries = …… double[5];

1. this if you know the values

double[] numbers = {10, 20, 30, 40, 50};

Application on Functions Overloading

what will be the output of this code

public class main {

static int day;

public static void main(String[] args) {

int a=10 ,b= 20;

char x='A', y='a';

System.out.println(larger(a, b));

System.out.println(larger(x,y));

}

}

what is the logical error here and corect it?

Scanner scan = new Scanner (System.in);

double [] sal = new double [5];

int i = 0;

for ( i=0;i<sal.length;i++)

sal[i]= scan.nextDouble();

System.out.println(sal[i]);

what will be the output of in this code

Scanner scan = new Scanner(System.in);

int i;

double Y=0;

for (i=0; i<5;i++)

{

System.out.println("Enter Salary For Employee No" + (i+1));

Y= scan.nextDouble();

}

System.out.println(Y);

if user enter in first case 2 and second case 3 and third case 4 and fourth case7 and fifth case 9

In Java, arithmetic expressions involving byte, short, or char are promoted to ……

EX

short x = 10;

x = x * 5;

System.out.print(x); }

x * 5 evaluates to an …., but you're trying to assign this ……result back to a short variable x.

So Compilation Error

To fix this, you need to cast the result to short

This how to make casting

Long x = 5;

int y = (int) x;

System.out.println(y);

Remember very important

instead of make this : char grade = scan.nextchar();

make this

……….

make a grade classification program ,It takes a single character input (representing a grade, e.g., A, B, C, etc.), processes the input using a switch statement, and outputs a corresponding message describing the grade's quality.

Make a program say if the number is even or odd

Attempting to use a ….. statement with a double or float will result in a compile-time error.

make this but by Enhanced For Loop

int x [] = {10,20,30};

for(int i=0;i<x.length;i++){

System.out.println(x[i]);i

the diffrence between ‘‘ and ““

Single quotes =….. , Double quotes = ……

double Y; // Y is …. but not …..

double Y = 0; // Y is … and ……

correct the following java code

Scanner scan = new Scanner(System.in);

char grade = scan.nextchar();

1. Dividing a double by a double gives a ….

EX

System.out.println(1.0 / 2.0); // 0.5

2. Dividing a float by a float gives a

EX

System.out.println(1.0f / 2.0f); // 0.5

type the image

Don't forget this👆👆

what is the outout of this code

for (int i=0; i<10;i++)

{

System.out.print("E");

}

for (int i=0; i<10;i++)

{

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

}

what is the 17&5?

THE DECREMENT OPERATOR is like INCREMENT but Used to decrease the value of a variable by ….

• decrement operator: --

tell me the output of this code

1. System.out.println("The sum is " + (1 + 3) );

2. System.out.println("The sum is + 1 + 3 );

i++ VS ++1

1. ++i increments the value of i by 1 and uses the new value in the statement

2. i++ increments the value of i by 1 and uses the original value in the statement

   Test Your self

   In the two images

int i1 = 2;

i1 *= 5 + 1;

→ Equivalent to:

….

→ Not to:

….

Logical AND operator: &&

Logical OR operator: ||

Logical NOT operator: !

Test you self

the x in the image is true or false?

corect the following sentence int x = 12383402047527075;

make a program calculate the Area of a Circle

type 3.14 with to ways with initialization

boolean is either ....or....

what is the difference in

int x = 123;

System.out.println(x);

AND

int x = 123;

System.out.println("x");

tell me each one in the image

1. {}

2. ()

3. / (its a division)

while loop

what will be the output

int count = 1;

while (count<=5) { //[

System.out.println("Hi");

++count;

}

Make the output in 3 ways

eyad

yasser

string is alot of....

tell me each one

int x = 123; is called ........

make this my number is : 123 with initialization

A …..: is a self-contained block of statements that perform a specific task.

Methods or functions

1. Correct the follwing code

public class main {

public static void main(String[] args) {

System.out.println("eyad");

System.out.print( 5+sum(2,10)) ;

////////////////

public static void sum(int x1, int x2)

{

int result=0;

result= x1+x2;

}

}

1. what will be the output of this code

   System.out.println("eyad");

   drawline('*' ,10);

   System.out.println("yasser");

   drawline('E',30);

   }

   ////////////////

   public static void drawline(char line, int length)

   {

   for (int i=0; i<length;i++)

   {

   System.out.print(line);

   }

   System.out.println();

   }

Local Variables

1. where is the error in this code

   {

   int sum =10;

   }

   System.out.println(sum);

2. what will be the output?

   public class main {

   static int sum=10;

   // called Global variable

   public static void main(String[] args) {

   {

   int sum =12;

   System.out.println(sum);

   }

   }}

3. what will be the output?

   public class main {

   static int sum=10;

   public static void main(String[] args) {

   {

   int sum =12;

   System.out.println(main.sum);

   }

   }}

   
   

passing array to function

For Remembring only

public class main {

public static void main(String[] args) {

// Creating an array

int[] numbers = {10, 20, 30, 40, 50};

// Passing array to function

int totalSum = calculateSum(numbers);

// Printing result

System.out.println("Total Sum: " + totalSum);

}

// Method to calculate sum of array elements

public static int calculateSum(int[] arr) {

int sum = 0;

for (int i = 0; i < arr.length; i++) {

sum += arr[i];

}

return sum;

}}

What will be the output of this code

System.out.print("\b\b = ");

In Constructors

• Classes can have special methods(functions) called constructors.

• A constructor is a method that is ….. called when an object is created.

Constructors are used to perform operations at the time an object is …..

• Constructors typically initialize instance fields and perform other object initialization tasks.

invoke=….

Remember this

class

object

attrbute

EX

Scanner scan = new Scanner(System.in);

Scanner is class (the data type of the object ) and we take from it object to can adjust it and we name it scan

we type new to make place in ram for it

➤ …… is a style of programming, a way of thinking about software construction.

this concept is called …..

Folder 1

package eyad;

}}

Folder 2

}}

THE OUTPUT WILL BE

——————————————————————————————————————

——————————————————————————————————————

folder 1

package eyad;

public class main {

}}

folder 2

package eyad;

public class Book {

// Instance variables (attributes) of the Book

// Constructor to initialize the Book object

// Method to display book information

}}

THE OUTPUT WILL BE

main folder

1. 
   

   why there is an error in title?

class folder

1. make set function to adjust (set) the title to become oop java

2. make get function to get the name of the title

Remember the meaning of the static keyword in the method signature public static void sum(int x1, int x2):

1. Belongs to the Class, Not to Objects

- The method belongs to the class itself, not to any specific instance (object) of the class

- You can call the method directly using the class name, without creating an object

2. Can be Called Without Object Creation

public class MathOperations {

}

Example to illustrate the differences:

Implementation on OOP

main folder

public class main {

public static void main(String[] args) {

}}

parent class folder

public class students {

}

child class folder

Identify the prototype of the default constructor.

Public class Solution {}

Which of the following code snippets will result in a compilation error in Java due to improper use of inheritance?

Explnation of inheritance

What will be the output of the following code?

Girl girl1 = new Girl();

girl1.speak();

ArrayList

Tell me the output of the follwing code

import java.util.ArrayList;

public class main {

public static void main(String[] args) {

ArrayList<String>list= new ArrayList<String>();

list.add("Ahmed");

list.add("Mohamed");

list.add("Ali");

System.out.println(list.size());

System.out.println(list);

System.out.println(list.get(2));

list.add(1, "Saad");

System.out.println(list);

list.remove(2);

System.out.println(list.size());

System.out.println(list);

}}

Correct the follwing code

ArrayList<int>list= new ArrayList<Int>();

Implimntation on ArrayList

Folder main

import java.util.Scanner;

public class main {

public static void main(String[] args) {

}}

Folder class

import java.util.Scanner;

import java.util.ArrayList;

public class Employee {

}

What will be the output of this code

1. class Hello { public static void main (String[] args) {

int a = 1;

switch (a) {

case 1: System.out.println ("One");

case 2: System.out.println ("Two");

case 3: System.out.println ("Three");

default: System.out.println ("Default");

}}

}

1. What will be the output if int x =2 instead of 1?

What is the output of the following code?

class Hello { public static void main (String[] args) {

final int a=10;

a++;

if (a%2==0) System.out.println ("even number");

else System.out.println ("odd number"); } }