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division problem?

variable type

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3 replies to this topic

#1 zeroradius


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Posted 10 October 2010 - 07:13 AM

I am trying to use java to divide a variable number inside a for loop by 3. For some reason it always has only one number after the decimal and it is always a 0. for what I am trying to do I need to know if 3 goes into it evenly so the numbers after the decimal are important for the algorithm I have made. I have tried using the variable types (double) & (float)

Note: Please do not suggest another way of finding if three goes evenly into something because 1) I may need to work with decimals in the future in which case this question is important for me to have answered. 2) this is for project euler and i would like to work out how to do things on my own; I'm only asking this because I'm confused with an aspect of the language not how to solve the problem. If my way is wrong I will discover it on my own and work out how to do it myself.

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#2 wim DC

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Posted 10 October 2010 - 07:52 AM

I'm only getting a zero as only decimal if i do int / int. (Ideone.com | 3TDo2)
     double dNumber = 5.0;
     double dThree = 3.0;
     int iThree = 3;
     int iNumber = 5;
     double result = dNumber / iThree ;
     System.out.println("double/int: " + result);
     result = iNumber / dThree ;
     System.out.println("int/double: " + result);
     result = dNumber/ dThree;
     System.out.println("double/double: " + result);
     result = iNumber/ iThree;
     System.out.println("int/int: " + result);

double/int: 1.6666666666666667
int/double: 1.6666666666666667
double/double: 1.6666666666666667
int/int: 1.0

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#3 Alexander



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Posted 10 October 2010 - 07:57 AM

Your description of the problem is too vague for us to guess what is going wrong without a sample code. An explicit integer cast after integer devision will do this (such as what oxano mentioned), which leads us to believe you hadn't casted it properly somewhere.
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All new problems require investigation, and so if errors are problems, try to learn as much as you can and report back.

#4 zeroradius


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Posted 10 October 2010 - 08:31 AM

that fixed it. I had set a double type variable to hold i/3 but i had set i as an int rather than a double. (>.<) My first time using a strongly typed language and doing math programmicly I usually just do data retrieval and writing. Sorry to waste your time and i should have posted the code, I forgot as i'm trying to get ready for work. thanks for the help. +rep

wont let me rep Null. Guess i can only give it one of you.
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