#Ec251
للي عندهم مشاكل مع الـflowcharts هادو مفروض يخلوك تتمكن منها 🤍:

1️⃣
شرح للأساس ( بالعربي )
https://youtu.be/hjsXyzBU-og

2️⃣
( بالعربي )
https://youtu.be/wvwAVS4yIeI

3️⃣
* للناس الي تحب المحتوى الانجليزي زيني 🤝🏻😄*
https://youtu.be/SWRDqTx8d4k

امتحان الجافا النصفي السيم الماضي #EC252

key solution
#EC252

#EC252
قائمة تشغيل رائعة
https://youtube.com/playlist?list=PLBlnK6fEyqRjKA_NuK9mHmlk0dZzuP1P5

#EC252

[Lecture 3]

• variables defined within a method (beside the parameters) are called helper variables.

• String methods:

.charAt();
return type: char.
function: returns the character at the specified index.

last character of a word:
word.charAt(word.length()-1);

.equals();
return type: boolean.
function: compares two strings. returns true if the strings are equal, and false if not.

.indexOf();
return type: int.
function: returns the position of the first found occurrence of specified characters in a string.
(when not found returns -1)

.length();
return type: int.
function: returns the length of a specified string.

.substring();
return type: String.
function: returns a new string which is the substring of a specified string.

when given one parameter:
substring ( index )
returns:
from index → end of original string.

when given two parameters:
returns:
string [index, index)

• Scanner methods:

.next();
reads a string from the keyboard up to the first encountered space.

.nextLine();
reads up to the a line break.

.nextInt();
reads an integer from the keyboard

• Object: something that has methods and a value.

• Integers (variables of type int) have no methods therefore are not objects.

• objects must be created with the new command, strings make an exception to this rule, using the new command when creating a String object is uncommon.

• Class: an object's type.

• Arraylists are the most used object-containers in java.

• Arraylists can be used to store unlimited number of objects.

• creating an arraylist from an array:
String[] array;
ArrayList<string> list = new ArrayList<>(Arrays.asList(array);

• creating an array from an arraylist:
String[] array1 = new String [list.size()];
list.toArray(array1);

• static max and min in the java.util.Collections class return the maximum and minimum element in an arraylist.

java.util.Collections.max(list)
java.util.Collections.min(list)

• we can use a for-each loop to go through the items of an ArrayList.

• ordering a string type arraylist by size means putting it in alphabetical order.

• ordering, reversing and shuffling an arraylist:
Collections.sort(arraylist);
Collections.reverse(arraylist);
Collections.shuffle(arraylist);

• an integer type arraylist is defined as ArrayList<Integer>

• when dealing with integer type arraylists,
arraylist.remove(4);
// removes number with index 4
arraylist.remove(Integer.valueOf(4));
// removes number 4 from arraylist

• truth values (boolean type variables)
if (boolean)
// is the same as boolean==true
if (!boolean)
// is the same as boolean==false