VARIABLES AND COMPARISON STATEMENT

• Variable - temporary storage for values and expressions
• Expressions -formulas that uses mathematical symbols
• Declaring a Variable:

  • var
  • case-sensitive
  • begin with a letter or an underscore

  ex: 1st- not accepted

  first- accepted

  var_1st - accepted
• Avoid using reserved words

  > reserved by JS
• Data Types:

  Integer - whole number

  Float - decimal point

  String - words

  Boolean - true or false
• Arithmetic Operation

  > tell the expression what operation to be done
• We can use addition to combine words. This is called "concatenation"
• Modulus

  > like division but answer is a reminder. if theres no reminder, the answer is zero.

  ex: 15%4=3

  4%2=0
• Increment ++ plus 1

  decrement -- minus 1
• x=5 y=7 z=0

  1. x=y++ -------> x=7 y=8
  2. x=++y ------> x=8, y=8
  3. z=x++ * ++y -----------> x=6, y=8, z=40
• Comparison Statement

  > evaluate the equality or difference between values or variables
• = - assigning x=3

  == - equal to 3==3

  === - value and data type 5===5(same value, same data type)
• 3!=2 - (3 is not equal to 2) True

  3!=3 - (3 is equal not to 3) False

  3>2 - (3 is greater than two) True
• Logical Operators

  > logic between expressions, variables etc.
• && and - true if both conditions are true

  - False if one condition is false

  II or - true even if only one condition is true

  - false if both conditions are false

  ! not - flips answer ex: !(3>2) ----> !(T) {not true}
• String literals are text enclosed in pairs of

  quotation marks.
• Numeric digits that are inside the quotation

  marks will be considered as a string and will

  lose then its numeric value.
• If the characters are not enclosed in

  quotation marks, JavaScript might interpret

  the characters as an object or a function.