Double.CompareTo Method in C# with Examples

The Double.CompareTo() method in C# compares the current double instance to another double value or object. It returns an integer that indicates whether the current value is less than, equal to, or greater than the compared value.

Syntax

Following are the two overloads of the Double.CompareTo() −

public int CompareTo(double value);
public int CompareTo(object value);

Parameters

• value − A double-precision floating-point number or object to compare with the current instance.

Return Value

The method returns an integer with the following meaning −

• Less than zero − Current instance is less than the compared value

• Zero − Current instance is equal to the compared value

• Greater than zero − Current instance is greater than the compared value

Using CompareTo with Double Values

Example − Equal Values

using System;

public class Demo {
   public static void Main() {
      double d1 = 150d;
      double d2 = 150d;
      Console.WriteLine("Double1 Value = " + d1);
      Console.WriteLine("Double2 Value = " + d2);
      Console.WriteLine("CompareTo Result = " + d1.CompareTo(d2));
      if (d1.CompareTo(d2) == 0) {
         Console.WriteLine("Both values are equal");
      }
   }
}

The output of the above code is −

Double1 Value = 150
Double2 Value = 150
CompareTo Result = 0
Both values are equal

Example − Different Values

using System;

public class Demo {
   public static void Main() {
      double d1 = 25.5;
      double d2 = 30.8;
      double d3 = 15.2;
      
      Console.WriteLine("d1 = " + d1);
      Console.WriteLine("d2 = " + d2);
      Console.WriteLine("d3 = " + d3);
      
      Console.WriteLine("d1.CompareTo(d2) = " + d1.CompareTo(d2));
      Console.WriteLine("d1.CompareTo(d3) = " + d1.CompareTo(d3));
      Console.WriteLine("d2.CompareTo(d1) = " + d2.CompareTo(d1));
   }
}

The output of the above code is −

d1 = 25.5
d2 = 30.8
d3 = 15.2
d1.CompareTo(d2) = -1
d1.CompareTo(d3) = 1
d2.CompareTo(d1) = 1

Using CompareTo with Object Parameter

Example

using System;

public class Demo {
   public static void Main() {
      double d1 = 20d;
      object d2 = 20d;
      object d3 = 35d;
      
      Console.WriteLine("Double Value = " + d1);
      Console.WriteLine("Object Value 1 = " + d2);
      Console.WriteLine("Object Value 2 = " + d3);
      
      Console.WriteLine("d1.CompareTo(d2) = " + d1.CompareTo(d2));
      Console.WriteLine("d1.CompareTo(d3) = " + d1.CompareTo(d3));
   }
}

The output of the above code is −

Double Value = 20
Object Value 1 = 20
Object Value 2 = 35
d1.CompareTo(d2) = 0
d1.CompareTo(d3) = -1

Comparison with Special Values

Conclusion

The Double.CompareTo() method provides a reliable way to compare double values, returning negative, zero, or positive integers based on the comparison result. It handles special floating-point values like NaN and infinity according to IEEE 754 standards, making it suitable for sorting and ordering operations.