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# Thread: java, cant figure this out

1. ## java, cant figure this out

i have the deitel 6th edition how to program java book.
On page 227 example 5.12 it says:

"Write an application that calculates the prduct of the odd integers from 1 to 15."

That is all it says...does it mean multiply all the odd numbers from 1 to 15? If so how do i do this....im not sure how to point out negative numbers.

• I'd probably get clarification from your teacher on that one. It can be interpreted a few different ways.

My interpretation would be that you need to come up with an algorithm to compute the product for every combination of odd integers from 1 - 15. Obviously you wouldn't manually write out every combination so that means you need one or more loops and some code to determine if the two integers are odd and then multiply them together and do so for every combination of odd integers. So for example you want to:

1x1 = 1
1x3 = 3
1x5 = 5
1x7 = 7
1x9 = 9
1x11 = 11
1x13 = 13
1x15 = 15
3x1 = 3
3x3 = 9
3x5 = 15
.
.
.
until you get to
15x15 = 225

Another question would be if it wants you to exclude duplicate calculations. Obviously you would have already done 1x3 so do you need to also include 3x1.

• I would guess it means 1x3x5x7x9x11x13x15. Technically thats what its asking, if it wanted spooksters example it should have said 'products' as you end up with multiple answers.
Ofcourse what a question asks for and what it wants are not always the same thing
I'm assuming the book has answers in it too? If so, ask a friend to look up the answer.

• Code:
```int product = 1;
for (int i = 1; i <= 15, i+=2)
product *= i;```
or you can do it recursively.
Code:
```public int oddFactorial(int i)
{
if (i == 1)
return 1;
return i * oddFactorial(i-2);
}```

• i tried both of those ways and cant seem to get either to work.

• Originally Posted by Ender
Code:
```int product = 1;
for (int i = 1; i <= 15, i+=2)
product *= i;```
or you can do it recursively.
Code:
```public int oddFactorial(int i)
{
if (i == 1)
return 1;
return i * oddFactorial(i-2);
}```
Why would you just provide a solution to what likely is a homework assignment? They didn't ask for a solution. They asked for an explanation of what the book was asking. The book he/she is using is used in the classroom for programming courses and those questions are normally assigned for homework.

• Originally Posted by Uber Fr0g
i tried both of those ways and cant seem to get either to work.
They do work. Can you not debug a comma? Learn to program.

Originally Posted by spookster
Why would you just provide a solution to what likely is a homework assignment? They didn't ask for a solution. They asked for an explanation of what the book was asking. The book he/she is using is used in the classroom for programming courses and those questions are normally assigned for homework.
I'm sorry, I know I shouldn't have given solutions, as he obviously posted his homework. I don't know why I answered like that... partly because it was early in the morning and I had not gotten a lot of sleep, and partly because of strange, subconscious, contemptuous reasons.

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