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C# round a number to any arbitrary digit of a double [duplicate]

This question already has answers here:
Round a double to x significant figures
(17 answers)
Round double in two decimal places in C#?
(8 answers)
Closed 1 year ago.
I am looking to round a double to any arbitrary digit to right or left of the decimal point.
Math.Round only works for digits to the right of the decimal point, and I need to be able to round to values the nearest 10s, 100s, 1000s, ...
Example of desired inputs/outputs:
Round(1234.56789, 0) == 1235
Round(1234.56789, -3) == 1234.568
Round(1234.56789, 3) == 1000
This problem differs from Round double in two decimal places in C#?
because I need to round values to positions to the left of the decimal point such as 1,2345,000 rounding to the nearest 10,000

If we take 10 to the power of the digit position, we can round the double to the arbitrary precision
public double RoundToDigit(double i, int digitPosition)
{
double precision = Math.Pow(10, digitPosition);
double result = Math.Round(i / precision, 0) * precision;
return result;
}

decimal/double/float won't store decimal places [duplicate]

This question already has answers here:
Why does integer division in C# return an integer and not a float?
(8 answers)
Closed 8 years ago.
I have tried this with decimal, double and float variables. I am dividing an integer by another integer and storing the result in a variable. None of the three data types will store decimal points, for example:
double d;
uint num1 = 20
uint num2 = 3
d = num1 / num2;
//d = 6.0
It is as if it is rounding to the nearest integer, help please?

You should cast either num1 or num2 as a decimal/double/float first before doing the division and storing the result..

When you do math with integers, the result is an integer. That's just how the operators are defined. To do double math, make num1, num2, or both doubles, or cast one of them to a double before calculating.

Unexpected double value in c# [duplicate]

This question already has answers here:
Why does integer division in C# return an integer and not a float?
(8 answers)
Closed 9 years ago.
Today i come with a problem and not able to figure out what is the issue with this simple statement
I Tried
double d =1/4;
expected ans for me is 0.25 but in reality ans is 0.0 why so ??
And what should we do if statement is in terms of integer variables like this
double a =(a-b)/(d+e);

Because what you done is here integer division. 1 / 4 always give you 0 as a result regardless which type you assing it.
.NET has 3 type of division. From 7.7.2 Division operator
Integer division
Floating-point division
Decimal division
From Integer division part;
The division rounds the result towards zero, and the absolute value of
the result is the largest possible integer that is less than the
absolute value of the quotient of the two operands.
If you want to 0.25 as a result, you should define one of your values as a floating point.
You can use one of these;
double d = 1d / 4d;
double d = 1d / 4;
double d = 1 / 4d;
And what should we do if statement is in terms of integer variables
like this
double a =(a-b)/(d+e);
I assume your a, b, d and e are integers, you should use one of these then;
double a = (double)(a-b) / (double)(d+e);
double a = (a-b) / (double)(d+e);
double a = (double)(a-b) / (d+e);

double d =1d/4;
should work.
If you don't specify the type of your numbers, it is treated as Integer. And integer 1/4 will be zero.

Use this:
double d = (double) 1 / 4;

/ Operator (msdn)
When you divide two integers, the result is always an integer. For
example, the result of 7 / 3 is 2. To determine the remainder of 7 /
3, use the remainder operator (%). To obtain a quotient as a rational
number or fraction, give the dividend or divisor type float or type
double. You can assign the type implicitly if you express the dividend
or divisor as a decimal by putting a digit to the right side of the
decimal point.
Try this:
double d = 1.0 / 4.0;

Float wrong calculation [duplicate]

This question already has answers here:
Why am I getting the wrong result when using float? [duplicate]
(4 answers)
Float is converting my values
(4 answers)
Closed 9 years ago.
The result must be 806603.77 but why I get 806603.8 ?
float a = 855000.00f;
float b = 48396.23f;
float res = a - b;
Console.WriteLine(res);
Console.ReadKey();

You should use decimal instead because float has 32-bit with 7 digit precision only that is why the result differs, on other hand decimal has 128-bit with 28-29 digit precision.
decimal a = 855000.00M;
decimal b = 48396.23M;
decimal res = a - b;
Console.WriteLine(res);
Console.ReadKey();
Output: 806603.77

A float (also called System.Single) has a precision equivalent to approximately seven decimal figures. Your res difference needs eight significant decimal digits. Therefore it is to be expected that there is not enough precision in a float.
ADDITION:
Some extra information: Near 806,000 (806 thousand), a float only has four bits left for the fractional part. So for res it will have to choose between
806603 + 12/16 == 806603.75000000, and
806603 + 13/16 == 806603.81250000
It chooses the first one since it's closest to the ideal result. But both of these values are output as "806603.8" when calling ToString() (which Console.WriteLine(float) does call). A maximum of 7 significant decimal figures are shown with the general ToString call. To reveal that two floating-point numbers are distinct even though they print the same with the standard formatting, use the format string "R", for example
Console.WriteLine(res.ToString("R"));

Because float has limited precision (32 bits). Use double or decimal if you want more precision.

Please be aware that just blindly using Decimal isn't good enough.
Read the link posted by Oded: What Every Computer Scientist Should Know About Floating-Point Arithmetic
Only then decide on the appropriate numeric type to use.
Don't fall into the trap of thinking that just using Decimal will give you exact results; it won't always.
Consider the following code:
Decimal d1 = 1;
Decimal d2 = 101;
Decimal d3 = d1/d2;
Decimal d4 = d3*d2; // d4 = (d1/d2) * d2 = d1
if (d4 == d1)
{
Console.WriteLine("Yay!");
}
else
{
Console.WriteLine("Urk!");
}
If Decimal calculations were exact, that code should print "Yay!" because d1 should be the same as d4, right?
Well, it doesn't.
Also be aware that Decimal calculations are thousands of times slower than double calculations. They are not always suitable for non-currency calculations (e.g. calculating pixel offsets or physical things such as velocities, or anything involving transcendental numbers and so on).

Division in C# to get exact value [duplicate]

This question already has answers here:
Why does integer division in C# return an integer and not a float?
(8 answers)
Closed 9 years ago.
If I divide 150 by 100, I should get 1.5. But I am getting 1.0 when I divided like I did below:
double result = 150 / 100;
Can anyone tell me how to get 1.5?

try:
double result = (double)150/100;
When you are performing the division as before:
double result = 150/100;
The devision is first done as an Int and then it gets cast as a double hence you get 1.0, you need to have a double in the equation for it to divide as a double.

Cast one of the ints to a floating point type. You should look into the difference between decimal and double and decide which you want, but to use double:
double result = (double)150 / 100;

Make the number float
var result = 150/100f
or you can make any of number to float by adding .0:
double result=150.0/100
or
double result=150/100.0

double result = (150.0/100.0)
One or both numbers should be a float/double on the right hand side of =

If you're just using literal values like 150 and 100, C# is going to treat them as integers, and integer math always "rounds down". You can add a flag like "f" for float or "m" for decimal to not get integer math. So for example result = 150m/100m will give you a different answer than result = 150/100.