2-Expression.js

/*
Definition: Something which evaluates to a value. Example: 3*a, a=b*4 
or 
Statements are made up of one or more expressions.
“expression” is a combination of values and functions that are combined and interpreted by the compiler to create a new value.
Statements are made up of one or more expressions. An expression is any reference to a variable or value, or a set of variable(s) and
value(s) combined with operators.
*/

//For example:

a = b * 2;
//This statement has four expressions in it:

//• 2 is a literal value expression.

//• b is a variable expression, which means to retrieve its current value.

//• b * 2 is an arithmetic expression, which means to do the multi‐plication.

//• a = b * 2 is an assignment expression, which means to assign

//the result of the b * 2 expression to the variable a (more on assignments later).

//A general expression that stands alone is also called an expression statement, such as the following:

b * 2;