Add exercises

Author: ChrisOwen101

exercises/A-expressions/README.md

@@ -0,0 +1,66 @@
+In JavaScript there are **expressions** and **statements**. We will use these words frequently to describe code.
+
+### Expression
+
+An expression returns a value. Sometimes we will say that an expression _evaluates to_ a value.
+
+The following are all examples of expressions:
+
+```js
+1 + 1; // returns 2
+("hello"); // returns "hello"
+2 * 4; // returns 8
+"hello" + "world"; // returns "helloworld"
+```
+
+We can take the value produced by an expression and assign it to a variable. That line of code would be called a statement.
+
+### Statement
+
+A statement is some code that performs an action. Here are some examples:
+
+```js
+var sum = 1 + 1; // action: assigns result of `1 + 1` to variable `sum`
+var greeting = "hello"; // action: assigns result of the expression "hello" to variable `greeting`
+console.log(2 * 4); // action: logs the result of `2 * 4` to the console
+sayGreeting(greeting); // action: calls the function `sayGreeting` with the parameter `greeting`
+```
+
+There are some other different types of statements that we will learn in the coming weeks.
+
+## Exercise
+
+You quickly find out the result of an expression by running node in a terminal window.
+
+* Open a terminal window
+* Run the command `node`
+* _You have now opened a node console (also called a REPL)_
+* Type an expression and press enter
+* To exit the console type Ctrl+C or type the command `.exit`
+
+Example from inside a terminal window:
+
+```bash
+$ node
+> 1 + 2
+3
+> "hello"
+'hello'
+> var greeting = "hello"
+undefined
+> greeting
+'hello'
+> console.log(greeting)
+hello
+undefined
+> .exit
+$
+```
+
+> Notice how when we execute an expression the value it produces is printed below it. When we execute a statement, we see `undefined` printed below. This is because statements don't produce values like expressions, they _do something_.
+
+* Write some more expressions in the node console
+* Assign some expressions to variables
+* Check the value of the variables
+
+Further reading on using the node console: https://hackernoon.com/know-node-repl-better-dbd15bca0af6

exercises/B-boolean-literals/README.md

@@ -0,0 +1,9 @@
+There is a special data type in JavaScript known as a **boolean** value. A boolean is either `true` or `false`, and it should be written without quotes.
+
+```js
+var codeYourFutureIsGreat = true;
+```
+
+## Exercise
+
+Head over to `exercise.js` and follow the instructions in the comments.

exercises/B-boolean-literals/exercise.js

@@ -0,0 +1,26 @@
+/*
+  BOOLEAN LITERALS
+  ----------------
+  This program needs some variables to log the expected result.
+  Add the required variables with the correct boolean values assigned.
+*/
+
+var codeYourFutureIsGreat = true;
+
+/* 
+  DO NOT EDIT BELOW THIS LINE
+  --------------------------- */
+
+console.log("Is Code Your Future great?", codeYourFutureIsGreat);
+console.log("Is Mozafar cool?", mozafarIsCool);
+console.log("Does 1 + 1 = 2?", calculationCorrect);
+console.log("Are there more than 10 students?", moreThan10Students);
+
+/* 
+  EXPECTED RESULT
+  ---------------
+  Is Code Your Future great? true
+  Is Mozafar cool? false
+  Does 1 + 1 = 2? true
+  Are there more than 10 students? false
+*/

exercises/C-comparison-operators/README.md

@@ -0,0 +1,29 @@
+We can also write **expressions** that return boolean values.
+
+Here's an expression that evaulates to a boolean.
+
+```
+1 > 2
+```
+
+* Can you work out what value this expression evaluates to?
+
+The `>` symbol in the expression is a **comparison operator**. Comparison operators compare two values. This operator checks to see if the number on the left is bigger than the number on the right.
+
+`1` is not bigger than `2` so this expression returns `false`.
+
+**More comparison operators**
+
+```
+>   greater than
+<   less than
+<=  less than or equal
+>=  greater than or equal
+=== same value
+!== not the same value
+```
+
+## Exercise
+
+* Open `exercise.js` and follow the instructions.
+* Open a node console, and write some expressions that use comparison operators

exercises/C-comparison-operators/exercise.js

@@ -0,0 +1,35 @@
+/*
+  BOOLEAN WITH COMPARISON OPERATORS
+  ---------------------------------
+  Using comparison operators complete the unfinished statements.
+  The variables should have values that match the expected results.
+*/
+
+var studentCount = 16;
+var mentorCount = 9;
+var moreStudentsThanMentors; // finish this statement
+
+var roomMaxCapacity = 25;
+var enoughSpaceInRoom; // finish this statement
+
+var personA = "Daniel";
+var personB = "Irina";
+var sameName; // finish this statement
+
+/* 
+  DO NOT EDIT BELOW THIS LINE
+  --------------------------- */
+console.log("Are there more students than mentors?", moreStudentsThanMentors);
+console.log(
+  "Is there enough space in the room for all students and mentors?",
+  enoughSpaceInRoom
+);
+console.log("Do person A and person B have the the same name?", sameName);
+
+/* 
+  EXPECTED RESULT
+  ---------------
+  Are there more students than mentors? true
+  Is there enough space in the room for all students and mentors? true
+  Do person A and person B have the the same name? false
+*/

exercises/D-predicates/README.md

@@ -0,0 +1,16 @@
+**Predicate** is a fancy word for a function that returns a boolean value.
+
+These functions are very useful because they let you test if a value satisifies certain requirements.
+
+```js
+function isNumber(value) {
+  return typeof value === "number";
+}
+
+isNumber(10); // returns true
+isNumber("hello"); // returns false
+```
+
+JavaScript programmers often give predicate functions a name that starts with a verb e.g. `isBig`, `isNegative`, `isActive`, `shouldUpdate`,
+
+Calling a predicate function is like asking a question: "is this value a number". The return value is the answer to your question.

exercises/D-predicates/exercise.js

@@ -0,0 +1,35 @@
+/*
+  Predicates
+  ---------------------------------
+  Write a predicate to predicates
+  The variables should have values that match the expected results.
+*/
+
+// Finish the predicate function to test if the passed number is negative (less than zero)
+function isNegative(number) {
+
+}
+
+// Finish the predicate function to test if the passed number is between 0 and 10
+function isBetweenZeroAnd10(number) {
+
+}
+
+/* 
+  DO NOT EDIT BELOW THIS LINE
+  --------------------------- */
+var number = 5;
+var numberNegative = isNegative(number);
+var numberBetweenZeroAnd10 = isBetweenZeroAnd10(number);
+console.log("The number in test is " + number);
+console.log("Is the number negative? " + numberNegative);
+console.log("Is the number between 0 and 10? " + numberBetweenZeroAnd10);
+
+/* 
+  EXPECTED RESULT
+  ---------------
+  The number in test is 5
+  Is the number negative? false
+  Is the number between 0 and 10? true
+*/
+

exercises/E-conditionals/README.md

@@ -0,0 +1,61 @@
+Like humans, computer programs make decisions based on information given to them. **Conditionals** are a way of representing these decisions in code.
+
+For example:
+
+* In a game, if the player has 0 lives, then the game is over
+* In a weather app, if rain is forecast, a picture of rain clouds is shown
+
+The most common type of conditional is the **if statement**.
+
+An if statment runs some code if a condition is met. If the condition is not met, then the code will skipped.
+
+```js
+var isHappy = true;
+
+if (isHappy) {
+  console.log("I am happy");
+}
+```
+
+The code in paratheses - e.g. `(isHappy)` - is the condition. The condition can be _any_ expression. The following are all valid conditions:
+
+```js
+// boolean value
+if (true) {
+  // do something
+}
+
+// variable assigned to boolean value
+if (isHappy) {
+  // do something
+}
+
+// equality operator returns a boolean value
+if (1 + 1 === 2) {
+  // do something
+}
+
+// comparison operator returns a boolean value
+if (10 > 5) {
+  // do something
+}
+
+// function call returns boolean value
+if (greaterThan10(5)) {
+  // do something
+}
+```
+
+An if statement runs code when a condition is met. What if the condition is not met? Sometimes you want to run an alternative bit of code.
+
+An **if...else statement** also runs code when the condition is _not_ met.
+
+```js
+var isHappy = true;
+
+if (isHappy) {
+  console.log("I am happy 😄");
+} else {
+  console.log("I am not happy 😢");
+}
+```

exercises/E-conditionals/exercise.js

@@ -0,0 +1,16 @@
+/*
+  Conditionals
+  ---------------------------------
+  Add an if statement to check Daniel's role in a CYF class.
+  If Daniel is a mentor, print out "Hi, I'm Daniel, I'm a mentor."
+  If Daniel is a student, print out "Hi, I'm Daniel, I'm a student."
+*/
+
+var name = "Daniel";
+var danielsRole = "mentor";
+
+/* 
+EXPECTED RESULT
+---------------
+Hi, I'm Daniel, I'm a mentor.
+*/

exercises/F-logical-operators/README.md

@@ -0,0 +1,39 @@
+There are three logical operators in JavaScript: `||` (OR), `&&` (AND), `!` (NOT).
+
+They let you write expressions that evaluate to a boolean value.
+
+Suppose you want to test if a number if bigger than 3 and smaller than 10. We can write this using logical operators.
+
+```js
+var num = 10;
+
+function satisfiesRequirements(num) {
+  if (num > 3 && num < 10) {
+    return true;
+  }
+
+  return false;
+}
+```
+
+We can test expressions with logical operators in a node console too:
+
+```sh
+$ node
+> var num = 10;
+undefined
+> num > 5 && num < 15
+true
+> num < 10 || num === 10
+true
+> false || true
+true
+> !true
+false
+> var greaterThan5 = num > 5
+undefined
+> !greaterThan5
+false
+> !(num === 10)
+false
+```