Mukesh R
JavaScript Operators and Operator Preferences
All of us are using mathematical basic operations very much in our lives. Adding, Subtracting, Dividing and etc. help us to act with numbers. In JavaScript like other programming languages we have these operations with specific operators.
An operator is a few characters that do a numerical, logical or other operations for us. In this lesson we want to illustrate numerical operators. The table below is sufficient for our aim:
|
Operator
|
Description
|
Example
|
Result
|
|
+
|
Adding one value to another (directly or by variables).
|
a1= 3.5
a2= 4 + a1 |
a2 becomes 7.5
|
|
-
|
Subtracting one value from another
|
b1= 3.5
b2= 4 - a1 - .5 |
b2 becomes 0
|
|
*
|
Multiplying one value by another
|
c1= 2
c2= c1*c1 +1 |
c2 becomes 5
|
|
/
|
Dividing one value by another
|
d1= 90
d2= d1/10 + 1 |
d2 becomes 10
|
|
%
|
Remained value from dividing of it by another value
|
e1= 7
e2= d1 % 4 |
e2 becomes 3
|
|
++
|
Add one to a variable
|
f= 8
f++ |
f becomes 9
|
|
--
|
Subtract one from a variable
|
g= 3.7
g-- |
g becomes 2.7
|
|
+= num
|
Add a number to a variable current value
|
h= 5
h += 2 |
h becomes 7
|
|
-= num
|
Subtract a number from a variable current value
|
i= 5
i -= 7 |
i becomes 3
|
|
*= num
|
Multiply a variable by a number
|
j= 5
j *= 2 |
j becomes 10
|
|
/= num
|
Divide a variable by a number
|
k= 5
k /= 2 |
k becomes 2.5
|
|
%= num
|
A variable value becomes its remaineder from its division by a number
|
l= 5
l %= 2 |
l becomes 1
|
The last point of this lesson is about operators orders. take a look at following statement and try to guess the result :
|
Code
|
Result
|
|
Result= 2+3*5+18/6+(7-4)%2
alert (Result) |
?
|
Parentheses are prior to other operators; the second place is for multiplication, dividing and percentaging operators ('*', '/', '%'); the one at left acts before the others from a category. The third place is for summing and subtracting ('+', '-'); and again the left operator is prior to the others.
So we can say that ((7-4= 3)) is calculated first, then ((3*5= 15)), after that ((18/6= 3)) and then ((3%2= 1)). Now it’s Summations and Subtractions that get ran ((2+15+3+1= 21)). The final result is 21.