found a solution

[belovedcrown.livejournal.com]

found this solution online to trim the excess decimals caused by the floating point error, but it doesn't round, which means the total pricing for each item i am trying to calculate may be off by a penny:

function dp(price)

{

string = "" + price;

number = string.length - string.indexOf('.');

if (string.indexOf('.') == -1)

return string + '.00';

if (number == 1)

return string + '00';

if (number == 2)

return string + '0';

if (number > 3)

return string.substring(0,string.length-number+3);

return string;

}

can someone help me make this round?

Comments

[insaint.livejournal.com]

What language is this written in?

For Java, check out DecimalFormat class:
http://java.sun.com/j2se/1.3/docs/api/java/text/DecimalFormat.html

For C++, use this code:
cout.setf(ios_base::fixed);
cout.precision(2);

Language-independent:
int temp = (price + 0.005) * 100;
double result = (double)temp / 100;
return double;

Hope this helps. And with that said, what in the hell does your post have to do with this community?

[ximinez]

I'm assuming this is related to your last post and you are using Javascript. The safest way to get rid of rounding errors is to get out of floating point and into integer. eg.

function FloatToInt(number, factor)
// factor is 1/precision, so if you want to round to two decimal
// places, precision is 0.01, and 1/0.01 is 100.
{
return Math.round(number * factor);
}

Now that you've got an int, you can divide it again by the factor

number / factor

to get the most accurate representation that Javascript can give you.

Alternatively, since the factor is a power of 10, you could just format it as a string

number.substring(0, number.length - 1 - 2) + "." + number.substring(number.length - 2, number.length - 1)

Another possibility, since you're working with money, is to do all of your computations in cents instead of dollars.

This is off the top of my head, so please double check my syntax, and function parameters.