Removing a decimal point in java

Question

I am wanting to store an integer named Amount, I want it to be stored in pence so if the user entered 11.45 it would be stored as 1145. What is the best way to remove the decimal point? Should I be using decimalFormatting in Java?

Edit:

It is entered in string format, was going to covert it to an int. I will give one of your solutions ago and let you know if it works but not sure which one would be the best.. Thanks everyone.

Is the user input in the form of a string or is it some numeric type. If the latter, what type? — Ted Hopp, Dec 10 '13 at 20:30
Please give us some feedback. What solutions are/aren't working? Which ones are on the right track for you? — Michael Yaworski, Dec 10 '13 at 20:51
it is entered as a string but should be an int, so I have convereted it into an int. using: -int tranAmount = Integer.valueOf(transactionAmount); — user3088476, Dec 12 '13 at 14:04

score 0 · Answer 1 · answered Dec 10 '13 at 20:29

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times it by 100 and cast as int. Use decimal formatting is double / float are too inaccurate which they may be for money

answered Dec 10 '13 at 20:29

exussum

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This only works if there are exactly two digits to the right of the radix point. – Steve P. Dec 10 '13 at 20:29

score -1 · Answer 2 · answered Dec 10 '13 at 20:33

-1

If the user input is in the form of a string (and the format has been verified), then you can strip out the decimal point and interpret the result as an integer (or leave it as a string without the decimal point).

String input = "11.45";
String stripped = input.replace(".", ""); // becomes "1145"
int value = Integer.parseInt(stripped);

If it's a float already, then just multiply by 100 and cast, as @user1281385 suggests.

answered Dec 10 '13 at 20:33

Ted Hopp

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@MartinMajer - OP said that the input was in a particular format. – Ted Hopp Dec 10 '13 at 20:36
"if the user entered 11.45" doesn't mean that he can't enter 11.4500. I think good solution is just to multiply it by 100 and cast to int. – Martin Majer Dec 10 '13 at 20:38
@MartinMajer - That requires converting to a float or double first. I was trying to avoid the possible rounding errors that might cost. – Ted Hopp Dec 10 '13 at 20:39

Michael Yaworski · Answer 3 · 2013-12-10T20:45:36.047

-1

Tested and works. Even if the user enters a number without a decimal, it will keep it as such.

double x = 11.45; // number inputted

String s = String.valueOf(x); // String value of the number inputted
int index = s.indexOf("."); // find where the decimal is located

int amount = (int)x; // intialize it to be the number inputted, in case its an int

if (amount != x) // if the number inputted isn't an int (contains decimal)
    // multiply it by 10 ^ (the number of digits after the decimal place)
    amount = (int)(x * Math.pow(10,(s.length() - 1 - index)));

System.out.print(amount); // output is 1145

// if x was 11.4500, the output is 1145 as well
// if x was 114500, the output is 114500

edited Dec 10 '13 at 20:45

answered Dec 10 '13 at 20:37

Michael Yaworski

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@MartinMajer To have it work for all cases. It's not complicated. Just read the comments. – Michael Yaworski Dec 10 '13 at 20:48
It's complicated if you can just multiply the number by 100, round it and convert to int. – Martin Majer Dec 10 '13 at 20:52
@MartinMajer That's a horrible solution. It doesn't cover all cases. What if the user enters 1.45? Then what? This isn't complicated. Read the comments and understand. Took me 2 minutes. All the OP has to do is copy and paste and it will work for **all** cases. – Michael Yaworski Dec 10 '13 at 20:53
@MartinMajer It's 4 lines of code for the solution. That is definitely not complicated. – Michael Yaworski Dec 10 '13 at 20:54
If the user enters 1.45, then multiplying and simple rounding + conversion will return 145, which is correct, I suppose. – Martin Majer Dec 10 '13 at 20:56
@MartinMajer lol yeah I meant to provide an example with a different in the fractional numbers. Example is 1.5. This isn't the place for semantics. What I've done is better solution. – Michael Yaworski Dec 10 '13 at 20:57
Sorry, but I still don't get it. Give me some examples where the simple solution with multiplying by 100 doesn't work and this one does. – Martin Majer Dec 10 '13 at 21:01
@MartinMajer I just said 1.5. Multiply that by 100 and its *150*. Seriously, stop. – Michael Yaworski Dec 10 '13 at 21:02
Seriously, the guy was talking about pence and that means money. And 1.5 pounds isn't 15 pence. – Martin Majer Dec 10 '13 at 21:06
@MartinMajer You're that immature to -1 my solution *that actually works for all cases* just because he's talking about pence? This solution is generic; yours isn't. If someone enters 11.4, yours will give incorrect output. You shouldn't be on this site if that's the reason you downvote a post. – Michael Yaworski Dec 10 '13 at 21:11
If you still think that the piece of code you've written is useful, try it with `1.0000000000001` and `1.000000000000000000001`. You will get some really interesting results. And please read something about floating-point numbers, you just cannot handle them this way. – Martin Majer Dec 10 '13 at 21:24
@MartinMajer again with the semantics. If he was worried out numbers being larger than `2^32 - 1`, (ridiculous semantics) then he can make an if statement to not take in a number that large, or just use an even *more complicated* string method. I know how to handle floating-point numbers. My solution is still better than any others on this page. I don't know why it's so hard for you to give someone credit. "Why so complicated?" Really? And you're going into floating-point numbers. – Michael Yaworski Dec 10 '13 at 21:30
@mikeyaworski I have used your code(just changed the variable names), but it is asking me to initialise the local variable: -double tranAmount;transactionAmount = String.valueOf(tranAmount);transactionAmount.indexOf("."); int amount = (int)tranAmount; // intialize it to be the number inputted, in case its an int if (amount != tranAmount) // if the number inputted isn't an int (contains decimal) // multiply it by 10 ^ (the number of digits after the decimal place) amount = (int)(tranAmount * Math.pow(10,(transactionAmount.length() - 1 - index))); – user3088476 Dec 13 '13 at 19:02
go to this website: http://pastie.org and post your code there. Select `Java` at the top right hand corner and then select `Create Paste`. Copy the link and paste it here. – Michael Yaworski Dec 13 '13 at 19:56

score -1 · Answer 4 · edited May 23 '17 at 11:49

-1

What about convert to float, multiply by 100 and then convert to int?

String pound = "10.45"; // user-entered string
int pence = (int)Math.round(Float.parseFloat(pound) * 100);

This might be also useful: Best way to parseDouble with comma as decimal separator?

edited May 23 '17 at 11:49

Community

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answered Dec 10 '13 at 20:43

Martin Majer

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Removing a decimal point in java

4 Answers4