1. Function Drills

For each of these functions, do the following:

Identify the function name, the function’s inputs (name/value) (parameters) and the function’s outputs (name/value) (things that are returned).
Describe what the function does in plain English.

function sayHello() {
  console.log("hello world");
}

function logTwoNumbers(first, second) {
  var sum = first + second;
  console.log(sum);
}

function addTwoNumbers(first, second) {
  var sum = first + second;
  return sum;
}

What’s the difference between `console.log(sum)` and `return sum`?

Try typing the following in your console:

var result = logTwoNumbers(1, 2);
result;

var sum = addTwoNumbers(1, 2);
sum;

Note that result is undefined, while sum is 3. Returning a result allows you to capture the result in a variable. Using console.log simply prints out the result on the console, but it can’t be saved into a variable.

2. Conditional Drills

Given these variables:

var bigNum = 1000;
var smallNum = 2;

Use the equals === operator to make a false statement and a true statement, and console.log the results
Use the less than < operator to make one true statement and one false statement, and console.log the results
Use the greater than > operator to make one true statement and one false statement, and console.log the results
Use the not equals != operator to make one true statement and one false statement, and console.log the results

3. Code Reading

DO NOT RUN THESE CODE EXAMPLES!!

The following is an exercise in reading code. Try to answer the following questions by only reading the code, without actually running it!

What is the output of the following code?

for (var i = 1; i <= 4; i++) {
  console.log("*");
}

var x = "|";
for (var i = 1; i <= 4; i++) {
  x = x + "*";
}
x = x + "|";
console.log(x);

for (var j = 1; j <= 3; j++) {
  var x = "|";
  for (var i = 1; i <= 4; i++) {
    x = x + "*";
  }
  x = x + "|";
  console.log(x);
}

What is the output of the following code?

function touch(elbow, ear) {
  console.log("touch your " + ear + " to your " + elbow);
}

var head = "shoulders";
var knees = "toes";
var elbow = "head";
var eye = "eyes and ears";
var ear = "eye";

touch(ear, elbow);
touch(eye, ear);
touch(head, "knees " + knees);

4. Code Writing

Write a function called myName that simply returns your name as a string.
- Store that string in a variable called thisIsMyName
- Log the value of that variable to the console.
Write a function called greeting that:
- Takes 1 argument: the hour of the day (24 hour time)
- Logs to the console “Good day” if the hour is less than 18, or “Good evening” otherwise.
- For example, greeting(10) should log “Good day”, and greeting(20) should log “Good evening”.
- Extra credit: Do not print anything when the hour parameter is invalid, such as greeting(24), greeting("hello"), or greeting(). (Decimals are OK, e.g. greeting(17.9) should log “Good day”).
Write a function called receipt that:
- Takes 1 argument, the subtotal (total cost of the meal, without tax or tip)
- Returns the total cost, based on a 9% tax and a 15% tip.
- For example, receipt(20) should return 24.8.

5. Extra Credit

Complete these if you have extra time and want to take on a challenge!