Pseudocoding

Pseudocoding

Explaining what your code does to a 3-year-old

Examples

Our task: add 5 to each item in an array. 

Pseudocode:

//iterate through the array

    //add 5 to each item

Actual code:

//iterate through the array
for (var i = 0; i < arr.length; i++) {
  //add 5 to each item
  arr[i] += 5;
}

Examples

Create a function, checkStore, that searches through our bookStore array for a user-inputted book

Pseudocode:

//declare a function that takes a bookname string as a parameter

    //iterate through the bookStore array

       //find the title of each book

       //check if the title matches the bookname

           //if so, pop up alert box with title, author, and price

           //ask the user if they want to add the item to their cart

               //if the user selects yes, add to their cart

    //if the book isn't found, alert the user that we don't have it

Example

You'll notice that each line of pseudocode gives us clear instructions for a task we can do. 

Do we follow the guidelines? 

• Rule #1: No actual code allowed.
• Rule #2: Explain what you're doing in English using very simple terms.
• Rule #3: Each line must be something that can be turned into code.
• Rule #4: You don't need to know how that line will be turned into code yet. 
• Rule #5: Indent pseudocode as you would real code to show control flow (loops, conditions).

When do we use it?

• At the start of any problem we don't have an obvious solution to
• Whenever we get stuck
• In pair programming to explain our approach
• When approaching any complex problem
• In technical interviews, no matter what

When do we use it?

All the time. 

It's super valuable. 

Be The Machine

• Practice "executing" your pseudocode with pretend inputs.
• Just as we like stepping through our actual code line by line to explain what it's doing, we can do the same with our pseudocode. 

Be the Machine

create a function that multiplies every even number in an input array by 10 and returns the modified array

//declare a function that takes an array as a parameter

    //iterate through that array

        //check to see if each item is even

             //if so, overwrite the array at that position with that item multiplied by 10

    //return the array

Let's "invoke" this with the array [1,2,3,4]

This helps you spot bugs before you even write code!

Be the Machine

create a function that multiplies every even number in an input array by 10 and returns the modified array

//declare a function that takes an array as a parameter

    //iterate through that array

        //check to see if each item is even

             //if so, overwrite the array at that position with that item multiplied by 10

    //return the array

Let's "invoke" this with the array [1,2,3,4]

This helps you spot bugs before you even write code!