Problem solving with Functions

Type: Homework
Class: SEI
Creator: GA Instructional Team
Topics: Problem solving with functions

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Instructions

1. Fork this repo.
2. Write your answers in app.js.
3. Follow the instructions below.
4. Once completed, send the repository link to the homework thread.

Hint: Remember your git skills for the commit history!

1. Verbal questions

Write answers to the following questions as comments.

1. What is the difference between a parameter and an argument?
2. Within a function, what is the difference between return and console.log?
3. What are the implications of the ability of a function to return a value?

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🔴 **Commit your work.**
The commit message should read:
"Commit 1 - Verbal questions".

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2. Calculate the Cube

Write a function calculateCube that takes a single number and prints the volume of a cube made from that number.

console.log(calculateCube(5));

=> 125

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🔴 **Commit your work.**
The commit message should read:
"Commit 2 - Cube Calculation".

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3. Is a Vowel?

Write a function isAVowel that takes a character (i.e. a string of length 1) and returns true if it is a vowel, false otherwise. The vowel could be upper or lower case.

console.log(isAVowel("a"));

=> true

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🔴 **Commit your work.**
The commit message should read:
"Commit 3 - Is a Vowel".

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4. Get Two Lengths

Write a function getTwoLengths that accepts two parameters (strings). The function should return an array of numbers where each number is the length of the corresponding string.

console.log(getTwoLengths("Hank", "Hippopopalous"));

=> [4, 13]

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🔴 **Commit your work.**
The commit message should read:
"Commit 4 - Two Lengths".

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5. Sum Array

Write a function sumArray that takes an array as an argument. The array should contain numbers. The function should return the sum of the numbers in the array. Do not use .reduce().

Expected result:

console.log(sumArray([1, 2, 3, 4, 5, 6]));
=> 21

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🔴 **Commit your work.**
The commit message should read:
"Commit 5 - Sum Array".

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6. Prime Numbers

A Prime number is a number that is not evenly divisible by another number except 1 and itself. If you want to read more deeply about it, go here. To test whether a number is Prime, you only need to test as far as the square root of that number. This is advisable for optimization and testing large numbers.

Step One

Write a function called checkPrime that will test whether a number is Prime. The function will return true (Boolean) if Prime, false if not. Hint: Check every number up to the square root. To do this, try a for loop.

Step Two

Write another function called printPrimes that will print (console log) all the Primes up to an arbitrary limit. For example, if you invoke your function with printPrimes(97), it will print all the Prime numbers up to and including 97. This function can call on the previous checkPrime function.

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🔴 **Commit your work.**
The commit message should read:
"Commit 6 - Prime Numbers".

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7. Print Longest Word

Write a function printLongestWord that accepts a single argument, an array of strings. The method should return the longest word in the array. In case of a tie, the method should return the word that appears first in the array.

console.log(printLongestWord(["BoJack", "Princess", "Diane", "a", "Max", "Peanutbutter", "big", "blob"]));

=> "Peanutbutter"

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🔴 **Commit your work.**
The commit message should read:
"Commit 7 - Longest Word".

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Bonus

Project Euler Problem

Project Euler problem #2

• Write a function that takes a parameter, a number. The function should print the Fibonacci sequence up to that number.

• Adjust the function to push the even numbered values into an array.

• Adjust the function to return the summed value of the array.

• Find the sum of the even numbered values that do not exceed four million.

A Needle in the Haystack

From Codewars Join CodeWars

Can you find the needle in the haystack?

Write a function findNeedle() that takes an array full of junk but contains one "needle"

After your function finds the needle it should return a message (as a string) that says:

"found the needle at postition" plus the index it found the needle so:

find_needle(['hay', 'junk', 'hay', 'hay', 'moreJunk', 'needle', 'randomJunk'])

Should return:

"found the needle at position 5"

Sum the Positive

From Codewars

Given an array, return the sum of only the positive numbers

[1, -4, 7, 12] => 1 + 7 + 12 = 20

Keep going!

Join CodeWars and find your own challenges to solve! Find a great one? Share it in slack!

Testing your work!

1. From inside this directory, run npm install in your terminal. This will download the testing dependencies for jest. Or you could follow these instructions to install jest.
2. Once you're ready to test your code: in the current directory, run npm run test in the terminal. Check the output for errors.
3. If there are any errors, make the adjustments where needed then run again.