Operators

Operators are symbols or keywords to perform a specific operation.

Assignment operator (=)

Often used for assigning variables to a value.

variable = value;

Using an integer variable integer,

int integer = 8;

Arithmetic operators

operator	description	expression
+	addition	a + b
-	subtraction	a - b
*	multiplication	a * b
/	division	a / b
%	modulo	a % b
Keynote of modulo operator: a % b returns the remainder of the expression. For example, if a is 4 and b is 3, it returns a remainder of 1

Compound assignment

They perform an arithmetic operation on the current value of the variable. It’s a shortcut to modify the variable itself without referencing it again.

expression	equivalent to…
y += x;	y = y + x;
x -= 5;	x = x - 5;
x /= y;	x = x / y;
price *= units + 1;	price = price * (units+1);

Increment and decrement (++, —)

variable++ or variable --

Only works for integer variables

These expressions increase or decrease the value of the same variable by one.

++x;
// Other similarities
x += 1;
x = x + 1;

Relational and comparison operators

These expressions are compared or related using the relational/comparison operators. For instance, if you were to compare the difference of two values, you’d use greater (>) or less than operator (<).

operator	description	examples
==	Equal to	(7 == 5) // evaluates to false
!=	Not equal to	(5 != 4) // evaluates to true
<	Less than	(3 < 2) // evaluates to false
>	Greater than	(6 > 6) // evaluates to true
<=	Less than or equal to	(5 <= 10) // evaluates to true
>=	Greater than or equal to	(8 >= 5) // evaluates to true

Expression of the variables in comparison works too in the evaluation.

(a == 5)     // evaluates to false, since a is not equal to 5
(a*b >= c)   // evaluates to true, since (2*3 >= 6) is true
(b+4 > a*c)  // evaluates to false, since (3+4 > 2*6) is false
((b=2) == a) // evaluates to true 

Logical operators (!, &&, ||)

The ! operator makes the boolean expression opposite (or NOT the expression) similar to inverting a value. For example, !true is the opposite of true, which is false.

!(5 == 5)   // evaluates to false because the expression at its right (5 == 5) is true
!(6 <= 4)   // evaluates to true because (6 <= 4) would be false
!true       // evaluates to false
!false      // evaluates to true 

The && logical operator is an AND operator that requires two expressions or more to be true. For example,

(true && true) // Evaluates true
((5==5) && (4*8 == 32)) // Evaluates true
((12*4 == 36) && (6 < 4)) // Evaluates false

On the other hand, || only requires at least one expression to be true. For example,

(true || false) // Evaluates true
((9 < 32) || ("oof" == "oof")) // Evaluates true
((12*4 == 36) || (8/4 == 1)) // Evaluates true