how to convert decimal points? [duplicate] - c#

This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
c# - How do I round a decimal value to 2 decimal places (for output on a page)
i have value of 1.564 and 1.565 i need round this value to 1.56 and 1.56,which function suitable for this in c#.

do a multiply by 100 followed by a floor and followed by a divide by hundred. I am sure that there is a better way of doing it though
Math.floor(n*100)/100

To remove the less significant digits (1.348 -> 1.34):
Math.Floor(number * 100) / 100;
To round the number to two decimals:
Math.Round(number, 2);
To represent it as a string, for display:
number.ToString("#.00");

Related

Convert int and float to 3 decimal places [duplicate]

This question already has answers here:
Formatting a float to 2 decimal places
(9 answers)
C# How to format a double to one decimal place without rounding
(6 answers)
Closed 11 months ago.
This is what I want to do:
if a double field has more than 3 decimal places then it should convert to 3 decimal figures and if no decimal places are present then it should convert to 3 decimals
e.g 12.878999 -> 12.878
120 -> 120.000
I cannot use string.Format() as I want the double field to stay double.
The first example requires Math.Round, eg Math.Round(d,3,MidPointRounding.ToZero).
The second isn't meaningful. Trailing decimal zeroes aren't significant. In the real types (float, double) they don't affect the storage of the number. The call Math.Round(120d, 3, MidpointRounding.AwayFromZero) will print 120 without a format string.
Displaying a double with three trailing zeroes is a formatting operation.
Update
From the comments it appears the actual problem is how to format a report sum in DevExpress Reports. All report engines allow specifying a format for fields and cells.
The Format Data page in the DevExpress Reports docs shows how to modify the FormatString property for a specific value
You can use Math.Round to achieve it
var value = Math.Round(12.878999, 3, MidpointRounding.ToZero);
For the integer type, you can do it this way
var value = 129 + 0.000m; //extend 3 decimals for an integer number

Why does this ulong divided by ulong give me 0? [duplicate]

This question already has answers here:
Why does integer division in C# return an integer and not a float?
(8 answers)
Closed 3 years ago.
I am grabbing total RAM of a computer system and available RAM and trying to work out what percentage is available.
I am using the following code:
double percent = my.Info.AvailablePhysicalMemory / my.Info.TotalPhysicalMemory;
and have also tried:
decimal percent = my.Info.AvailablePhysicalMemory / my.Info.TotalPhysicalMemory;
I am sure it's an issue with the type but I am unsure why both methods give a result of 0.
The actual values are Total: 17072574464 and Available: 8746000384. The values come back from the system cast as ulong. So what does percent always equal 0? If I put the numbers in directly it works fine. Just can't use the ulong variables - hence why I am sure it's my lack of experience with types in C# that is the problem.
You are trying to divide an integer by an integer, which always rounds down. You need to convert to a floating point number before you divide; for example:
double percent = my.Info.AvailablePhysicalMemory * 1.0 / my.Info.TotalPhysicalMemory;

Math.Sqrt(2/3) returns 0 [duplicate]

This question already has answers here:
Why does integer division in C# return an integer and not a float?
(8 answers)
Closed 6 years ago.
I am really confused why this is happening, my code:
double x = Math.Sqrt(2/3);
MessageBox.Show(x.ToString());
Displays 0.
The answer is
0.8164, I know I will also have to use Math.Round to round this up, but for the moment the issue is I'm getting 0
The problem is caused by automatic integer evaluation of the numbers. Use:
double x = Math.Sqrt(2f/3f);
MessageBox.Show(x.ToString());
2 / 3 is an integer operation, what you want is 2.0 / 3 which means I want to use floating point numbers.
What you consider an Intereger is different from what you know from Maths. In programming languages it means that a result of an int-operation is allways an integer in itself.
In your example 2 / 3 is an integer-operation which means the result is rounded down to the nearest integer, which is zero. To avoid this indicate that at least one of your operands should be treates as some floating-point value, either using 2.0 or 2f (alternativly 3.0 or 3f).

Math.Round() call in .NET using negative precision [duplicate]

This question already has answers here:
Built in .Net algorithm to round value to the nearest 10 interval
(8 answers)
Closed 9 years ago.
I have a requirement to perform rounding of values with negative precision. As far as I've checked, Math.Round() in .NET does not support negative precision. For example:
ROUND(43.34566,-1)
The above returns 40.
Please suggest how to achive this.
Move the comma to the precision you want to give back and then round.
double n = 43.34566;
double roundingValue = -1;
double precision = Math.Pow(10, roundingValue);
n *= precision;
double result = Math.Round(n, 0) / precision;
ROUND(43.34566 / 10,0) * 10 will work; generalise as appropriate.
Quite simple really:
Math.Round(num / Math.Pow(10.0, -(precision))) * Math.Pow(10.0, -(precision));
//this won't work for positives but oh well

How to round to a specific decimal accuracy? [duplicate]

This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Round a double to 2 significant figures after decimal point
I have a value var i = 0.69999980926513672. I need to round this value to 0.7 is there a built-in method that will do this?
Use one of:
System.Math.Round (i, 1, MidpointRounding.ToEven);
System.Math.Round (i, 1, MidpointRounding.AwayFromZero);
The difference is how it handles numbers that are equidistant to the rounding point (e.g., 0.65 in your case could either go to 0.7 or 0.6).
Here is a answer I gave to another question which holds much more information.
You are looking for the Math.Round method.
//first param is number to round
//second param is the accuracy to use in the rounding (number of decimal places)
Math.Round(i, 2)
Console.WriteLine(System.Math.Round(0.69999980926513672d, 1));
-- edit
wow, you blink and there are 5 other answers!
http://msdn.microsoft.com/en-us/library/system.math.round%28VS.71%29.aspx
Use the Math.Round method:
double i = 0.69999980926513672;
double result = Math.Round(i, 2);

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