Thread: Need some math help

Originally Posted by Norm

In your example what would be the values in the array at the end of each of the steps?

X=1234

Y[4] (creates an array of way with 4 shelves/things to store numbers in)

Y[0] = 1
Y[1] = 2
Y[2] = 3
Y[3] = 4

Next I add 7 to the numbers

Y[0] = 1+7 This would be 8
Y[1] = 2+7 This would be 9
Y[2] = 3+7 This would be 10
Y[3] = 4+7 This would be 11

Then I do that get the remainder after dividing by 10 thing

Y[0] = Y[0] % 10 This becomes 8
Y[1] = Y[1] % 10 This becomes 9
Y[2] = Y[2] % 10 This becomes 1
Y[3] = Y[3] % 10 This becomes 2

Not sure if these outcomes are 100% correct. I'm trying to do a couple different home works at once.

Originally Posted by Norm

What math steps would need to be done to "undo" the % operator? Make a list of numbers that are possible values in this program (7-16), apply % to them and then look at what would need to be done to get back the original numbers.
For example:
7 % 10 = 7 Nothing needed to restore 7
16 % 10 = 6 add 10 to get 16

So...if a number is between 8 and 9 then just subtract 7 from it? if its anything else add 10 to it, then subtract 7?

There are only 10 different numbers so you should be able to see how to convert each one of them to the original value.

is it possible to combine the 4 elements in the array into a single int?

Yes. You need to define the value in each slot's relationship to the other slots in the array.

Remember how our number system works:
1234 is the sum of these 4 values:
1*1000
2*100
3*10
4*1
The factors are 10 to a power.

have java read the length of the initial int

I assume you mean how many digits a number displayed in base 10 takes. int values are stored in binary format in a 32 bit area of memory.

One way to see the number of digits would be by testing the value against the smallest and highest value with the desired number of digits. For 2 digits: 10 to 99
Also since most user input is read as a String, use a String class method to determine the length of the String.

wew! Thanks for the help again all. Grade 100! Thanks to your help.

Forum Question now, I have another math question(s) for my next hw assignment. Would it be better to just start a new topic, or to keep going with this old one?

Start a new thread for a new problem.