Please help us improve Stack Overflow. Take our short survey. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. How do I restrict a float value to only two places after the decimal point in C? Ask Question. Asked 12 years, 4 months ago. Active 1 year, 10 months ago. Viewed k times. How can I round a float value such as Improve this question.
Sakib Arifin 12 12 bronze badges. Tyler Tyler. You cannot properly round the number itself, because float and double aren't decimal floating-point - they are binary floating-point - so rounding to decimal positions is meaningless. You can round the output, however. It's not meaningless; it's inexact. There's quite a difference. What kind of rounding you're expecting?
Half-up or Rounding to nearest even? Add a comment. Active Oldest Votes. Improve this answer. Dale Hagglund Dale Hagglund Can it be modified to support rounding to arbitrary precision? If the former, make what I hope are obvious adjustments to the constant ; otherwise, do the exact same calculations shown above, just with whatever multi precision library you're using.
DaleHagglung The former, thank you. Is the adjustment to replace with pow 10, int desiredPrecision? This should be really easy to see if you write out some decimal values by hand and play around with multiples of Suppose you're working with the value 1. The operation available to you is round to integer.
So, how do you move the first three decimal places so that they're left of the decimal point? Now you can round that value to an integer. Can I make this work with doubles too somehow? Doesn't seem to do the job I want : using floor and ceil. Show 12 more comments. It only print 2 decimal points. Mani Kandan 3 3 silver badges 18 18 bronze badges. Andrew Coleson Andrew Coleson 9, 8 8 gold badges 29 29 silver badges 30 30 bronze badges.
This way is better because there is no loss of precision. Community Bot 1 1 1 silver badge. John Carter John Carter Upvoted for addressing what may be the question behind the question or the question that should have been behind the question! That's a rather important point. Actually Float has 11 to 12 digit for precission. That should be enough to address Continue on C — Int, char validation functions…. Prev Next C trunc function:. Like it? Please Spread the word! This function returns the absolute value of an integer.
This function returns the nearest integer which is less than or equal to the argument passed to this function. This function returns nearest integer value which is greater than or equal to the argument passed to this function.
First it is important to know that floating point numbers are approximated. See the link provided by Greg Hewgill to understand why this problem is not fully solvable. Realistically that's not possible. For many values there are no precise representations, so you can't simply truncate to a number of digits. If you really need to be able to store only a limited number of digits, I suggest you use a fixed-precision data type instead.
If its for comparison between values, perhaps you should consider using the epsilon test. Due to how floats are normally stored on computers, there'd probably be inaccuracies. That's what you get for using floats, though. Similar to other answers, BUT you must not forget that round, floor and trunc are different by definition. See the definition and output example of the following:. In this case we need to trucate with a precision of 4 decimals and get rid of non-significant decimals:.
How are we doing? Please help us improve Stack Overflow. Take our short survey. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Asked 13 years, 1 month ago.
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