 Introduction to JavaScript : Expressions and Operations

# Expressions and Operations

Expressions and operators play very important roles in any programming language. To understand this, let's take a simple expression of

`5+7=12`

Here in this expression, `5` and `7` are referred to as operands and `+` is known as the operator while the whole expression is referred to as the operation of addition. JavaScript provides a number of different operators:

• Arithmetic Operators
• Comparison Operators
• Logical Operators
• Assignment Operators
###### Arithmetic Operators

These are the arithmetic operators that are supported in JavaScript:

1. Addition using the symbol `+` for example `2 + 3 = 5`
2. Subtraction using the symbol `–` for example `10 - 20` will equals `-10`
3. Multiplication using the symbol `*` for example `10*20` will equals `200`
4. Division using the symbol `/` for example `20/10` gives `2`
5. Modulus using the symbol `%` which provides the remainder of an integer division for example `20 % 10` will be `0`
6. Increment using the symbol `++` which increases the value of integer by one. For example, `10++` will give `11`
7. Decrement using the symbol `--` which decreases the value of integer by one. For example, `10--` will give `9`.
###### Comparison Operators

Comparison operators provide a means to compare two values. The following comparison operators are supported.

• Equal operator using the symbol `==` for comparing two values and giving true result if they are equal to each other. For Example, `10 == 20` is not true (false).
• Not equal operator using the symbol `!=` for comparing two values and giving true result if they are not equal to each other. For Example, `10 != 20` is true.
• Greater than operator using the symbol `>` for comparing two values and returning true if the left side is greater than the right side. For Example, `20 > 10` is true.
• Less than operator using the symbol `<` for comparing two values and returning true if the left side is less than the right side. For Example, `10 < 20` is true.
• Greater than or equal to operator using the symbol `>=` for comparing two values and returning true if the left operand is greater than or equal to the right operand. For Example, `20 >= 10` is true.
• Less than or equal to operator using the symbol <= forcomparing two values and returning true if the left operand is less than or equal to the right operand. For Example, `20 <= 10` is not true.
###### Logical Operators
• Logical 'And' using the symbol && returning true if both operands of the expression are true.

For example if `x=true` and `y=true` then `x`` && y` is true and if `x=true` and `y=false` then `x && y` is false

• Logical 'Or' using the symbol || returning true if any of the operands is true.

For example if x=true and y=false then x || y is true and if x=false and y=false then x || y is false

• Logical 'Not' using the symbol ! reverses the logical state of an operand. The logical 'Or' is a unary operator.

For example if `x=true` then `!x` is false.

###### Assignment Operators
• Simple Assignment Operator using the symbol `=`, assigns the value of the right side to the left side.

For example, given y` = 5` and z` = 10,` then `x = y+z` assigns the value `15` to `x`

• Addition and Assignment Operator using the symbol `+=`, performs the addition of the left operand to the right operand and then assigns the result to the left operand.

For example, given `x` = 5 and z = 11, then x += z assigns the value 16 to x

• Subtraction and Assignment Operator using the symbol `-=`, performs the subtraction of the right operand from the left operand and then assigns the result to the left operand.

For example, given x = 11 and z = 5, then x -= z assigns the value 6 to x

• Multiplication and Assignment Operator using the symbol `*=`, performs the multiplication of the right operand with the left operand and then assigns the result to the left operand.

For example, given x = 11 and z = 5, then x *= z assigns the value `55` to x

• Division and Assignment Operator using the symbol /=, performs the division of the left operand by the right operand and then assigns the result to the left operand. For example, X/= Z is equal to X=X­/Z

For example, given x = 10 and z = 5, then x /= z assigns the value `2` to x

• Modulus and Assignment Operator using the symbol `%=`, performs modulus using two operands and assigns the result to the left operand. For example, X%= Z is equal to X=X­%A.

For example, given x = 11 and z = 5, then x %= z assigns the value `1` to x ##### Introduction to JavaScript
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Introduction to JavaScript