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C# / .NET - Math.Round() method example
0 points
Math.Round is a static method that returns a number that is rounded to the closest integer number.
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using System;2
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public class Program4
{5
public static void Main(string[] args)6
{7
Console.WriteLine( Math.Round( 5.0 )); // 58
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Console.WriteLine( Math.Round( 2.49 )); // 210
Console.WriteLine( Math.Round( 2.50 )); // 311
Console.WriteLine( Math.Round( 2.51 )); // 312
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Console.WriteLine( Math.Round(-2.49 )); // -214
Console.WriteLine( Math.Round(-2.50 )); // -215
Console.WriteLine( Math.Round(-2.51 )); // -316
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Console.WriteLine( Math.Round( 0.999 )); // 118
Console.WriteLine( Math.Round( 1.001 )); // 119
Console.WriteLine( Math.Round(-1.001 )); // -120
}21
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namespace System2
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public static class Math4
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// ...6
public static decimal Round(decimal d) { ... }7
public static decimal Round(decimal d, int precision) { ... }8
public static decimal Round(decimal d, int precision, MidpointRounding mode) { ... }9
public static decimal Round(decimal d, MidpointRounding mode) { ... }10
public static double Round(double value) { ... }11
public static double Round(double value, int precision) { ... }12
public static double Round(double value, int precision, MidpointRounding mode) { ... }13
public static double Round(double value, MidpointRounding mode) { ... }14
// ...15
}16
}
| Syntax | Syntax example is above. |
| Parameters |
|
| Result | Rounded number value (primitive value). |
| Description | Round is a static method that returns a number that is rounded to the closest integer number. |
This section contains a custom function that shows how to round number with precision to n places.
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using System;2
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public class Program4
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static double RoundPrecised(double number, int precision)6
{7
double power = Math.Pow(10, precision);8
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return Math.Round(number * power) / power;10
}11
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public static void Main(string[] args)13
{14
Console.WriteLine( RoundPrecised( 5 , 0 ) ); // 515
Console.WriteLine( RoundPrecised( 5.0, 0 ) ); // 516
Console.WriteLine( RoundPrecised( 0.5, 0 ) ); // 017
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Console.WriteLine( RoundPrecised( 1.2345, 0 ) ); // 119
Console.WriteLine( RoundPrecised( 1.2345, 1 ) ); // 1.220
Console.WriteLine( RoundPrecised( 1.2345, 2 ) ); // 1.2321
Console.WriteLine( RoundPrecised( 1.2345, 3 ) ); // 1.23422
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Console.WriteLine( RoundPrecised( -1.2345, 0 ) ); // -124
Console.WriteLine( RoundPrecised( -1.2345, 1 ) ); // -1.225
Console.WriteLine( RoundPrecised( -1.2345, 2 ) ); // -1.2326
Console.WriteLine( RoundPrecised( -1.2345, 3 ) ); // -1.23427
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Console.WriteLine( RoundPrecised( 12345, -1 ) ); // 1234029
Console.WriteLine( RoundPrecised( 12345, -2 ) ); // 1230030
Console.WriteLine( RoundPrecised( 12345, -3 ) ); // 1200031
}32
}This section contains custom round function implementation.
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using System;2
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public class Program4
{5
static double RoundNumber(double value)6
{7
if (value < 0.0)8
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double rest = (value % 1.0);10
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if (rest < -0.5)12
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rest += 1.0;14
}15
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return value - rest;17
}18
else19
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value += 0.5;21
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return value - (value % 1.0);23
}24
}25
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public static void Main(string[] args)27
{28
// Example:29
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Console.WriteLine( RoundNumber( 5 ) ); // 531
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Console.WriteLine( RoundNumber( 2.49 ) ); // 233
Console.WriteLine( RoundNumber( 2.50 ) ); // 334
Console.WriteLine( RoundNumber( 2.51 ) ); // 335
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Console.WriteLine( RoundNumber( 0.999 ) ); // 137
Console.WriteLine( RoundNumber( 1.001 ) ); // 138
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Console.WriteLine( RoundNumber( -2.49 ) ); // -240
Console.WriteLine( RoundNumber( -2.50 ) ); // -241
Console.WriteLine( RoundNumber( -2.51 ) ); // -342
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Console.WriteLine( RoundNumber( -1.001 ) ); // -144
}45
}