classwork

pset1.js

@@ -15,6 +15,16 @@ What are the types of the following expressions and what do they evaluate to, an
 
 ******************/
 
+/*  17 is a number and evalutates to 17.
+    1 + 2 * 3 + 4 is a number and evaluates to 11 because of PEMDAS rules.
+    800/ 80 / 8 is a number and evaluates to 1.25 because of PEMDAS rules.
+    400 > 200 is a boolean and evaluates to true because the statement is true.
+    1 !== 1 is a boolean and it evaluates to false because the statement is false.
+    true || false is a boolean and it evaluates to true because a statement can be true or false.
+    true && false is a boolean and it evaluates to false because a statement can not be true and false.
+    20 % 6 is a number and it evaluates to 2 because that is the remainder of 20/6.
+    'a' + 'b' is a string and it evaluates to ab because they are combined by the + operator. 
+ */
 
 
 /******************
@@ -29,7 +39,12 @@ What will the following return? Why?
 
 ******************/
 
-
+/*  typeof 4 will return number because 4 is a number.
+    type of 'hello' will return string because anything in quotes is read as a string.
+    typeof true will return boolean because anything with a true or false value is a boolean.
+    2 === 1 || 3 === 4 will return false because this statement is a boolean because of the === and || operators and 
+    when both values are evaluated and compared, both sides are false therefore the entire statement is false.
+*/
 /******************
 PROBLEM 3:
 
@@ -46,7 +61,13 @@ For reference, here is a truth table for the expression A && B:
 
 ******************/
 
+/*  |   A   |   B   | A || B| 
+    | true  | true  | true  |
+    | false | true  | true  |
+    | true  | false | true  |
+    | false | false | false | 
 
+*/
 
 /******************
 PROBLEM 4:
@@ -63,6 +84,12 @@ For reference, here is a truth table for the expression A && !B:
 
 ******************/
 
+/*  |   A   |   B   | !A    |  !B   | !A &&!B | 
+    | true  | true  | false | false | true    |
+    | false | true  | true  | false | false   |
+    | true  | false | false | true  | false   |
+    | false | false | true  | true  | true    | 
+
 
 
 /******************
@@ -79,7 +106,11 @@ For reference, here is a exp of a step-by-step evaluation:
 
 ******************/
 
-
+/*  2 + 3 * 2 + 1
+    2 +   6   + 1
+       8 + 1
+        9
+*/       
 
 /******************
 PROBLEM 6:
@@ -89,7 +120,11 @@ Write a step-by-step evaluation for the following expression (remember order of
 
 ******************/
 
-
+/* 4 / 2 + 8 / 4
+     2   + 8 / 4
+     2   +   2 
+         4
+*/
 
 /******************
 PROBLEM 7:
@@ -100,11 +135,23 @@ Write a step-by-step evaluation for the following expression: 'ca' + 'ter' + 'pi
 
 ******************/
 
+/* 'ca' + 'ter' + 'pi' + 'llar'
+    'cater' + 'pi' + 'llar'
+         'caterpi' + 'llar'
+              'caterpillar'
+*/              
 
 /******************
 PROBLEM 8:
 
 Write a step-by-step evaluation for the following expression: 2 * 4 === 8 && 'car' + 'pool' === 'carpool'.
 
+******************/
 
-******************/
+/*  2 * 4 === 8 && 'car' + 'pool' === 'carpool'
+      8 === 8 && 'car' + 'pool' === 'carpool'
+      true && 'car' + 'pool' === 'carpool'
+         true && 'carpool' === 'carpool'
+         true && true
+             true            
+*/