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JavaScript

Posted by Tony McCabe
Tony McCabe
8,445 Points

Create a Variable named "mevol" and assign the value 16 to it using an octal number literal

octal number literals // 06 === 6 // 07 === 7 " " " " 012 === 10 013 === 11 " " " " My code was: var mevol = 018; before used: var mevol = 016; and the error message say's add 2 to the decimal number 016. I added two accord to the chart above but keep's comming up with error code <code> var = 021 </code> what am I doing wrong tried many different ways including 0216 and many more

9 Answers

Jamie Hinojosa
Jamie Hinojosa
6,982 Points

James, does this help? You can see the pattern here. Rember it's base 8. 07=7 010=8 011=9 012=10 013=11 014=12 015=13 016=14 017=15 020=16 021=17 022=18 023=19 024=20 025=21 026=22 027=23 030=24

Anish Hallan
Anish Hallan
2,334 Points

How would this work for 4 digits? I understand how it works for 3 but cannot work out how it would work for 4.

Thanks in advance

Michelle Pepe
Michelle Pepe
Courses Plus Student 2,076 Points

Thanks Jamie

Kyle Brooks
Kyle Brooks
6,753 Points
Kyle Brooks
Kyle Brooks
6,753 Points

Tony, you have to add two for each octal. In this case, it would be adding 4, which should give you var mevol = 020 (If I recall my answer correctly on the code challenge).

Bob Sutherton
Bob Sutherton
20,160 Points
Bob Sutherton
Bob Sutherton
20,160 Points

But why is this? I was following the same logic as Tony which says that if 01 = 8 then 018 = 8 + 8 which should give 16. What are we missing? Why do you suddenly add four places instead of two?

Andy Hammond
Andy Hammond
5,415 Points

018 wouldn't technically exist because Octal only goes until 7. (0 1 2 3 4 5 6 7 and restart.)

Tony McCabe
Tony McCabe
8,445 Points
Tony McCabe
Tony McCabe
8,445 Points

Nice thanks very much!!

Sherrie Gossett
Sherrie Gossett
14,924 Points

Think of the "2" (in the answer 020) as representing two "8"s. So 0 + two 8s = 16 + 0 = the answer: 16. Another example: 030. Think of the 3 as representing three 8s or 24. So 030 = 24.

Dewi Tjin
Dewi Tjin
2,275 Points
Dewi Tjin
Dewi Tjin
2,275 Points

When would you even need to use this?

Sherrie Gossett
Sherrie Gossett
14,924 Points

Apparently, per the video, it's rare in JS. It seems the information was included so that coders will avoid placing a zero before their numbers. Found this on stackoverflow: "Octal is used as a shorthand for representing file permissions on UNIX systems."

Regan O'Neill
Regan O'Neill
12,714 Points
Regan O'Neill
Regan O'Neill
12,714 Points

Thank you for your help here! The video did a poor job of explaining how this works. In order to be more helpful and communicate the nature of octal numbers, they should use another example than just numbers with a middle digit of 1 - For example) 012, 015, etc.