MathF.Round() Method in C# with Examples

The MathF.Round() method in C# is used to round a float value to the nearest integer or to a specified number of fractional digits. This method provides several overloads to handle different rounding scenarios and midpoint rounding behaviors.

Syntax

Following are the different overloads of the MathF.Round() method −

public static float Round(float x);
public static float Round(float x, int digits);
public static float Round(float x, int digits, MidpointRounding mode);
public static float Round(float x, MidpointRounding mode);

Parameters

• x − The float number to be rounded.

• digits − The number of fractional digits in the return value.

• mode − Specifies how to round x if it is midway between two numbers using the MidpointRounding enumeration.

Return Value

Returns a float number nearest to x that contains a number of fractional digits equal to digits.

Using MathF.Round() with Basic Rounding

Example

using System;

public class Demo {
    public static void Main() {
        float val1 = 15.20f;
        float val2 = 3.10f;
        float val3 = 7.75f;
        float val4 = 9.25f;
        
        Console.WriteLine("Original values:");
        Console.WriteLine("val1 = " + val1);
        Console.WriteLine("val2 = " + val2);
        Console.WriteLine("val3 = " + val3);
        Console.WriteLine("val4 = " + val4);
        
        Console.WriteLine("\nRounded values:");
        Console.WriteLine("Rounded (val1) = " + MathF.Round(val1));
        Console.WriteLine("Rounded (val2) = " + MathF.Round(val2));
        Console.WriteLine("Rounded (val3) = " + MathF.Round(val3));
        Console.WriteLine("Rounded (val4) = " + MathF.Round(val4));
    }
}

The output of the above code is −

Original values:
val1 = 15.2
val2 = 3.1
val3 = 7.75
val4 = 9.25

Rounded values:
Rounded (val1) = 15
Rounded (val2) = 3
Rounded (val3) = 8
Rounded (val4) = 9

Using MathF.Round() with Specified Decimal Places

Example

using System;

public class Demo {
    public static void Main() {
        float val1 = 10.23898f;
        float val2 = 20.878788f;
        float val3 = 15.12345f;
        
        Console.WriteLine("Original values:");
        Console.WriteLine("val1 = " + val1);
        Console.WriteLine("val2 = " + val2);
        Console.WriteLine("val3 = " + val3);
        
        Console.WriteLine("\nRounded to different decimal places:");
        Console.WriteLine("Rounded (val1, 2) = " + MathF.Round(val1, 2));
        Console.WriteLine("Rounded (val2, 3) = " + MathF.Round(val2, 3));
        Console.WriteLine("Rounded (val3, 1) = " + MathF.Round(val3, 1));
        Console.WriteLine("Rounded (val3, 4) = " + MathF.Round(val3, 4));
    }
}

The output of the above code is −

Original values:
val1 = 10.23898
val2 = 20.878788
val3 = 15.12345

Rounded to different decimal places:
Rounded (val1, 2) = 10.24
Rounded (val2, 3) = 20.879
Rounded (val3, 1) = 15.1
Rounded (val3, 4) = 15.1235

Using MathF.Round() with MidpointRounding

Example

using System;

public class Demo {
    public static void Main() {
        float val = 2.5f;
        
        Console.WriteLine("Original value: " + val);
        Console.WriteLine("ToEven (Banker's): " + MathF.Round(val, MidpointRounding.ToEven));
        Console.WriteLine("AwayFromZero: " + MathF.Round(val, MidpointRounding.AwayFromZero));
        
        val = 3.5f;
        Console.WriteLine("\nOriginal value: " + val);
        Console.WriteLine("ToEven (Banker's): " + MathF.Round(val, MidpointRounding.ToEven));
        Console.WriteLine("AwayFromZero: " + MathF.Round(val, MidpointRounding.AwayFromZero));
        
        val = -2.5f;
        Console.WriteLine("\nOriginal value: " + val);
        Console.WriteLine("ToEven (Banker's): " + MathF.Round(val, MidpointRounding.ToEven));
        Console.WriteLine("AwayFromZero: " + MathF.Round(val, MidpointRounding.AwayFromZero));
    }
}

The output of the above code is −

Original value: 2.5
ToEven (Banker's): 2
AwayFromZero: 3

Original value: 3.5
ToEven (Banker's): 4
AwayFromZero: 4

Original value: -2.5
ToEven (Banker's): -2
AwayFromZero: -3

MidpointRounding Modes Comparison

Conclusion

The MathF.Round() method provides flexible rounding capabilities for float values in C#. It supports rounding to the nearest integer, to a specified number of decimal places, and offers different midpoint rounding strategies to handle edge cases where values are exactly halfway between two numbers.