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23 lis 2019 · There’s a function called std::round in the <cmath> header file that rounds a real number to the nearest integer. You can use that to round to the nearest tenth by computing std::round(10 * x) / 10.0, or to the nearest hundredth by calling std::round(100 * x) / 100.0. (Do you see why that works?) You seem to be more interested in rounding up rather than rounding to the nearest value, which ...
13 lip 2010 · 3. To do it generically, use the same function you've got, but shift the input up or down some decimals: double round( double value, int precision ) {. const int adjustment = pow(10,precision); return floor( value*(adjustment) + 0.5 )/adjustment; } (Note that you'll have to #include <math.h> or #include <cmath> to use the pow function.
We have the following and and header <tgmath.h> for type-generic macros. #include <math.h> double round (double x); float roundf (float x); long double roundl (long double x); If you cannot compile this, you have probably left out the math library. A command similar to this works on every C compiler I have (several).
5. You can multiply it by 1000 and then round (or truncate) it; this will give you a value 1000 times the 3-decimal place value. Note that, if you divide it by 1000 to get the 'rounded' value, you may end up w/ more than 3 decimal places (due to round off error). answered Jan 16, 2013 at 23:25. Scott Hunter.
6 sty 2011 · If you want -6.0, then you would need floor (-5.9), so the code would have to be: round = f > 0 ? std::ceil(f) : std::floor(f) ; The question is whether you are rounding up as ceil () does, or rather rounding away from zero (up in magnitude rather than up in value) which the above code does? edited Jan 6, 2011 at 17:30.
Do. answer = static_cast<float>(static_cast<int>(number * 10.)) / 10.; If instead you are just trying to display the value with that precision, try setprecision: cout << setprecision(1) << number << endl; In your code you're comparing a float to a double. This can only end badly (as will any floating point comparisons).
17 paź 2022 · Using setprecision method. C++ has one special formatting function named setprecision () to set the precision value up to n decimal places. To use this method, we need to import the iomanip library. It also needs to specify we are using fixed decimal places. The syntax will be like the below −.
