JavaScript Arithmetic

The typical scenario for handling numbers is arithmetic.

JavaScript Arithmetic Operators

Arithmetic operators perform arithmetic operations on numerical values ( literals or variables).

operator description
+ Addition
- Subtraction
* Multiplication
** Power (ES2016)
/ Division
% Coefficient
++ Increment
-- Decrement

Arithmetic operators

Typical arithmetic operations operate on two numerical values.

These two numbers can be literals:

instance

var x = 7 + 8;

try it yourself

Or variable:

instance

var x = a + b;

try it yourself

Or expression:

instance

var x = (7 + 8) * a;

try it yourself

Operators and operands

In arithmetic operations, numbers are calledOperands.

The operation (performed between two operands) is defined byoperatorDefinition.

Operands operator Operands
7 + 8

Addition

AdditionOperator (+) Addend:

var x = 7;
var y = 8;
var z = x + y;

try it yourself

Subtraction

SubtractionOperator (-) Subtrahend.

var x = 7;
var y = 8;
var z = x - y;

try it yourself

Multiplication

MultiplicationOperator (*) Multiplier.

var x = 7;
var y = 8;
var z = x * y;

try it yourself

Division

DivisionOperator (/) Divisor.

var x = 7;
var y = 2;
var z = x / y;

try it yourself

Coefficient

CoefficientOperator (%) Returns the remainder of the division.

var x = 7;
var y = 2;
var z = x % y;

try it yourself

Note:In arithmetic, the division of two integers produces a quotient and a remainder.

Note:In mathematics, the result of the modulus operation is the remainder of the arithmetic division.

Increment

IncrementOperator (++) Increments the value.

var x = 7;
x++;
var z = x;

try it yourself

Decrement

DecrementOperator (--) Decrements the value.

var x = 7;
x--;
var z = x;

try it yourself

Exponent

The exponentiation operator (**) raises the first operand to the power of the second operand.

instance

var x = 5;
var z = x ** 2;          // The result is 25

try it yourself

The result of x ** y is the same as Math.pow(x,y):

instance

var x = 5;
var z = Math.pow(x,2);   // The result is 25

try it yourself

Operator precedence

Operator precedence (Operator precedence) describes the order of operations performed in arithmetic expressions.

instance

var x = 200 + 50 * 2;

try it yourself

What is the result of 250 * 2 or 200 + 100 in the previous example?

Is addition or multiplication given priority?

In traditional school mathematics, multiplication is given priority.

multiplication（*）and division（%）and addition（+）and subtraction（-）has a higherprecedence.

At the same time, (just like in school mathematics) you can change the precedence by using parentheses:

instance

var x = (200 + 50) * 2;

try it yourself

When using parentheses, the operators within the parentheses are calculated first.

When multiple operators have the same precedence (such as addition and subtraction), their calculations are performed from left to right:

instance

var x = 200 + 50 - 2;

try it yourself

JavaScript operator precedence values

value operator description instance
20 ( ) expression grouping (3 + 4)
　 　 　 　
19 . member person.name
19 [] member person["name"]
19 () function call myFunction()
19 new create new Date()
　 　 　 　
17 ++ postfix increment i++
17 -- postfix decrement i--
　 　 　 　
16 ++ prefix increment ++i
16 -- prefix decrement --i
16 ! Λογική αρνητική !(x==y)
16 typeof type typeof x
　 　 　 　
15 ** power (ES7) 10 ** 2
　 　 　 　
14 * multiply 10 * 5
14 / divide 10 / 5
14 % modulus division 10 % 5
　 　 　 　
13 + add 10 + 5
13 - subtract 10 - 5
　 　 　 　
12 << left shift x << 2
12 >> right shift x >> 2
12 >>> right shift (unsigned) x >>> 2
　 　 　 　
11 < less x < y
11 <= less than or equal x <= y
11 > greater x > y
11 >= greater than or equal x >= y
11 in property in object "PI" in Math
11 instanceof instance of object instanceof Array
　 　 　 　
10 == equal x == y
10 === strictly equal x === y
10 != Μη ισοδύναμη x != y
10 !== Στατική μη ισοδύναμη x !== y
　 　 　 　
9 & Λογική και x & y
8 ^ Λογική XOR x ^ y
7 | Λογική ή x | y
6 && Λογική και x && y
5 || Λογική αρνητική x || y
4 ? : Τελική συνθήκη ? "Ναι" : "Όχι"
　 　 　 　
3 = Ανάθεση x = y
3 += Ανάθεση x += y
3 -= Ανάθεση x -= y
3 *= Ανάθεση x *= y
3 %= Ανάθεση x %= y
3 <<= Ανάθεση x <<= y
3 >>= Ανάθεση x >>= y
3 >>>= Ανάθεση x >>>= y
3 &= Ανάθεση x &= y
3 ^= Ανάθεση x ^= y
3 |= Ανάθεση x |= y
　 　 　 　
2 yield Παύση συνάρτησης yield x
1 , Κόμμα 7, 8

Σημείωση:Καταχρώμενη ή προτεινόμενη τεχνολογία (ECMASScript 2016 ή ES7)

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