CSP 20-21 U7L07 Level 04

CS Principles Coding and Debugging Help
1

Hello, I think there’s an issue with the solution code in U7 L07 Level 04:

Link to the project or level: This link is to code.org’s solution example:
https://studio.code.org/projects/applab/JEmsWD7dpcEnLbJvZRT-AKtGL2aKK_poF1wPcHaNMnQ/view
What I expect to happen: “-5 is odd?” should return true, -5 is an odd number and -5%2 equals 1.
What actually happens: “-5 is odd?” returns false instead.
What I’ve tried: The solution code works for the other test cases, just not for -5, and the function formula (number%2) == 1 is correct mathematically.

Thank you in advance.

2

From the ECMAScript 5.1 definition “The sign of the result equals the sign of the dividend.” Meaning that -5 % 2 will be -1 as per the language specification.

So that means there is a bug in the solution. Here is one of many possible fixes :

function isOdd (number) {
  return number % 2 == 1 || number % 2 == -1;
}

Another:

function isOdd (number) {
  return Math.abs(number % 2) == 1;
}

You should open a bug report.

3

This would work too

function isOdd(number) {
    return !!(number%2)
}

Number%2 will always return 0 if it’s even
Since 0 is the only number that is falsy, anything odd would be truthy. The not not operator will convert it to a boolean.

Another very short solution is

function isOdd(number){
    return number%2!=0
}
4

Excellent, thank you Don for the fast and on-target reply. Keep up the good support, makes a big difference for teachers like me taking up this new course.

5

Excellent, thank you for the fast and on-target reply, those are clever solutions. Keep up the good support, makes a big difference for teachers like me taking up this new course.

6

Hi Everyone,

Thanks for the teamwork here! This has been fixed and it will be live online in the next day or two!

Kaitie