8- java language basics part2

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LANGUAGE BASICS PART2 JAVA BY AMR ELGHADBAN

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Page 1: 8- java language basics part2

LANGUAGE BASICS PART2JAVA

BY AMR ELGHADBAN

Page 2: 8- java language basics part2

JAVA : Language Basics Part2

Operators Precedence

postfix expr++ expr--

unary ++expr --expr +expr -expr ~ !

multiplicative * / %

additive + -

shift << >> >>>

relational < > <= >= instanceof

equality == !=

bitwise AND &

bitwise exclusive OR ^

bitwise inclusive OR |

logical AND &&

logical OR ||

ternary ? :

assignment = += -= *= /= %= &= ^= |= <<= >>= >>>=

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JAVA :Language Basics part2

OPERATORS▸ Operators are special symbols that perform specific

operations on one, two, or three operands, and then return a result.

▸ The operators in the following table are listed according to precedence order.

▸ The closer to the top of the table an operator appears, the higher its precedence.

▸ Operators with higher precedence are evaluated before operators with relatively lower precedence.

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JAVA :Language Basics part2

OPERATORS▸ In general-purpose programming, certain operators tend

to appear more frequently than others.

▸ for example, the assignment operator "=" is far more common than the unsigned right shift operator ">>>".

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JAVA :Language Basics part2

OPERATORS▸ The Simple Assignment Operator

▸ One of the most common operators that you'll encounter is the simple assignment operator "=". You saw this operator in the Bicycle class; it assigns the value on its right to the operand on its left:

▸ int cadence = 0;

▸ int speed = 0;

▸ int gear = 1;

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JAVA :Language Basics part2

OPERATORS▸ The Arithmetic Operators

▸ Java provides operators that perform addition, subtraction, multiplication, and division.

▸ The only symbol that might look new to you is "%", which divides one operand by another and returns the remainder as its result.

Operator Description+ Additive operator (also - Subtraction operator* Multiplication operator/ Division operator % Remainder operator

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JAVA :Language Basics part2

▸ class ArithmeticDemo {

▸ public static void main (String[] args) {

▸ int result = 1 + 2;

▸ // result is now 3

▸ System.out.println("1 + 2 = " + result);

▸ int original_result = result;

▸ result = result - 1;

▸ // result is now 2

▸ System.out.println(original_result + " - 1 = " + result);

▸ original_result = result;

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JAVA :Language Basics part2

▸ result = result * 2;

▸ // result is now 4

▸ System.out.println(original_result + " * 2 = " + result);

▸ original_result = result;

▸ result = result / 2;

▸ // result is now 2

▸ System.out.println(original_result + " / 2 = " + result);

▸ original_result = result;

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JAVA :Language Basics part2

▸ result = result + 8;

▸ // result is now 10

▸ System.out.println(original_result + " + 8 = " + result);

▸ original_result = result;

▸ result = result % 7;

▸ // result is now 3

▸ System.out.println(original_result + " % 7 = " + result);

▸ }

▸ }

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JAVA :Language Basics part2

▸ This program prints the following:

▸ 1 + 2 = 3

▸ 3 - 1 = 2

▸ 2 * 2 = 4

▸ 4 / 2 = 2

▸ 2 + 8 = 10

▸ 10 % 7 = 3

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JAVA :Language Basics part2

▸ You can also combine the arithmetic operators with the simple assignment operator to create compound assignments. For example, x+=1; and x=x+1; both increment the value of x by 1.

▸ The + operator can also be used for concatenating (joining) two strings together, as shown in the following ConcatDemo program:

▸ class ConcatDemo {

▸ public static void main(String[] args){

▸ String firstString = "This is";

▸ String secondString = " a concatenated string.";

▸ String thirdString = firstString+secondString;

▸ System.out.println(thirdString);

▸ }

▸ }

▸ By the end of this program, the variable thirdString contains "This is a concatenated string.", which gets printed to standard output.

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JAVA :Language Basics part2

OPERATORS▸ The Arithmetic Operators

▸ Java provides operators that perform addition, subtraction, multiplication, and division.

▸ The only symbol that might look new to you is "%", which divides one operand by another and returns the remainder as its result.

Operator Description+ Unary plus operator indicates positive value

(numbers are positive without this, - Unary minus operator negates an expression++ Increment operator, increments a value by 1- - Decrement operator, decrements a value by 1 ! Logical complement operator, inverts the

value of a boolean

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JAVA :Language Basics part2

▸ class UnaryDemo {

▸ public static void main(String[] args) {

▸ int result = +1;

▸ System.out.println(result); // result is now 1

▸ result--;

▸ System.out.println(result); // result is now 0

▸ result++;

▸ System.out.println(result); // result is now 1

▸ result = -result;

▸ System.out.println(result); // result is now -1

▸ boolean success = false;

▸ System.out.println(success); // false

▸ System.out.println(!success); // true } }

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JAVA :Language Basics part2

▸ The increment/decrement operators can be applied before (prefix) or after (postfix) the operand.

▸ The code result++ and ++result will both end in result being incremented by one.

▸ The only difference is that the prefix version (++result) evaluates to the incremented value, whereas the postfix version (result++) evaluates to the original value.

▸ If you are just performing a simple increment/decrement, it doesn't really matter which version you choose.

▸ But if you use this operator in part of a larger expression, the one that you choose may make a significant difference.

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JAVA :Language Basics part2

▸ The following program, PrePostDemo, illustrates the prefix/postfix unary increment operator:

▸ class PrePostDemo {

▸ public static void main(String[] args){

▸ int i = 3;

▸ i++;

▸ System.out.println(i); // prints 4

▸ ++i;

▸ System.out.println(i); // prints 5

▸ System.out.println(++i); // prints 6

▸ System.out.println(i++); // prints 6

▸ System.out.println(i); // prints 7

▸ }

▸ }

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JAVA :Language Basics part2

▸ The Equality and Relational Operators

▸ The equality and relational operators determine if one operand is greater than, less than, equal to, or not equal to another operand. The majority of these operators will probably look familiar to you as well. Keep in mind that you must use "==", not "=", when testing if two primitive values are equal.

▸ == equal to

▸ != not equal to

▸ > greater than

▸ >= greater than or equal to

▸ < less than

▸ <= less than or equal to

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JAVA :Language Basics part2

▸ class ComparisonDemo {

▸ public static void main(String[] args){

▸ int value1 = 1;

▸ int value2 = 2;

▸ if(value1 == value2)

▸ System.out.println("value1 == value2");

▸ if(value1 != value2)

▸ System.out.println("value1 != value2");

▸ if(value1 > value2)

▸ System.out.println("value1 > value2");

▸ if(value1 < value2)

▸ System.out.println("value1 < value2");

▸ if(value1 <= value2)

▸ System.out.println("value1 <= value2”); } }

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JAVA :Language Basics part2

▸ Output:

▸ value1 != value2

▸ value1 < value2

▸ value1 <= value2

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JAVA :Language Basics part2

▸ Another conditional operator is ?:, which can be thought of as shorthand for an if-then-else statement (discussed in the Control Flow Statements section of this lesson). This operator is also known as the ternary operator because it uses three operands. In the following example, this operator should be read as: "If someCondition is true, assign the value of value1 to result. Otherwise, assign the value of value2 to result."

▸ The following program, ConditionalDemo2, tests the ?: operator:

▸ class ConditionalDemo2 {

▸ public static void main(String[] args){

▸ int value1 = 1;

▸ int value2 = 2;

▸ int result;

▸ boolean someCondition = true;

▸ result = someCondition ? value1 : value2;

▸ System.out.println(result); } }

▸ Because someCondition is true, this program prints "1" to the screen. Use the ?: operator instead of an if-then-else statement if it makes your code more readable; for example, when the expressions are compact and without side-effects (such as assignments).

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JAVA :Language Basics part2▸ The following quick reference summarizes the operators supported by the Java programming language.

▸ Simple Assignment Operator

▸ = Simple assignment operator

▸ Arithmetic Operators

▸ + Additive operator (also used for String concatenation)

▸ - Subtraction operator

▸ * Multiplication operator

▸ / Division operator

▸ % Remainder operator

▸ Unary Operators

▸ + Unary plus operator; indicates positive value (numbers are positive without this, however)

▸ - Unary minus operator negates an expression

▸ ++ Increment operator increments a value by 1

▸ -- Decrement operator decrements a value by 1

▸ ! Logical complement operator inverts the value of a boolean

▸ Equality and Relational Operators

▸ == Equal to

▸ != Not equal to

▸ > Greater than

▸ >= Greater than or equal to

▸ < Less than

▸ <= Less than or equal to

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JAVA :Language Basics part2

▸ The following quick reference summarizes the operators supported by the Java programming language.

▸ Conditional Operators

▸ && Conditional-AND

▸ || Conditional-OR

▸ ?: Ternary (shorthand for if-then-else statement)

▸ Type Comparison Operator

▸ instanceof Compares an object to a specified type

▸ Bitwise and Bit Shift Operators

▸ ~ Unary bitwise complement

▸ << Signed left shift

▸ >> Signed right shift

▸ >>> Unsigned right shift

▸ & Bitwise AND

▸ ^ Bitwise exclusive OR

▸ | Bitwise inclusive OR

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THANKS WISH YOU A WONDERFUL DAY

▸ Skype : amr_elghadban

▸ Email :[email protected]

▸ Phone : (+20)1098558500

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