Math.Sign() Method in C#

The Math.Sign() method in C# is used to return an integer that indicates the sign of a number. It returns +1 for positive numbers, -1 for negative numbers, and 0 for zero.

Syntax

The Math.Sign() method has multiple overloads to handle different numeric types −

public static int Sign(sbyte value);
public static int Sign(short value);
public static int Sign(int value);
public static int Sign(long value);
public static int Sign(float value);
public static int Sign(double value);
public static int Sign(decimal value);

Return Value

The method returns an int value −

• -1 if the value is negative

• 0 if the value is zero

• +1 if the value is positive

Using Math.Sign() with Integer Types

using System;

public class Demo {
   public static void Main() {
      short val1 = 1;
      int val2 = 20;
      long val3 = -3545465777;
      int val4 = 0;
      
      Console.WriteLine("Short Value = " + val1);
      Console.WriteLine("Sign (Short Value) = " + Math.Sign(val1));
      Console.WriteLine("Int32 value = " + val2);
      Console.WriteLine("Sign (Int32 Value) = " + Math.Sign(val2));
      Console.WriteLine("Long value = " + val3);
      Console.WriteLine("Sign (Long Value) = " + Math.Sign(val3));
      Console.WriteLine("Zero value = " + val4);
      Console.WriteLine("Sign (Zero Value) = " + Math.Sign(val4));
   }
}

The output of the above code is −

Short Value = 1
Sign (Short Value) = 1
Int32 value = 20
Sign (Int32 Value) = 1
Long value = -3545465777
Sign (Long Value) = -1
Zero value = 0
Sign (Zero Value) = 0

Using Math.Sign() with Floating-Point Types

using System;

public class Demo {
   public static void Main() {
      decimal val1 = 20.5m;
      double val2 = -35.252d;
      float val3 = 0.0f;
      
      Console.WriteLine("Decimal Value = " + val1);
      Console.WriteLine("Sign (Decimal Value) = " + Math.Sign(val1));
      Console.WriteLine("Double value = " + val2);
      Console.WriteLine("Sign (Double Value) = " + Math.Sign(val2));
      Console.WriteLine("Float value = " + val3);
      Console.WriteLine("Sign (Float Value) = " + Math.Sign(val3));
   }
}

The output of the above code is −

Decimal Value = 20.5
Sign (Decimal Value) = 1
Double value = -35.252
Sign (Double Value) = -1
Float value = 0
Sign (Float Value) = 0

Practical Example with Sign Interpretation

using System;

public class Demo {
   public static void Main() {
      double[] numbers = { -42.5, 0, 15.8, -100 };
      
      foreach (double num in numbers) {
         int sign = Math.Sign(num);
         string interpretation = GetSignInterpretation(sign);
         Console.WriteLine($"Number: {num}, Sign: {sign}, Interpretation: {interpretation}");
      }
   }
   
   public static string GetSignInterpretation(int sign) {
      if (sign == 0)
         return "Zero";
      else if (sign < 0)
         return "Negative";
      else
         return "Positive";
   }
}

The output of the above code is −

Number: -42.5, Sign: -1, Interpretation: Negative
Number: 0, Sign: 0, Interpretation: Zero
Number: 15.8, Sign: 1, Interpretation: Positive
Number: -100, Sign: -1, Interpretation: Negative

Common Use Cases

• Conditional logic based on number positivity or negativity

• Mathematical calculations requiring sign determination

• Data validation to check if values are positive, negative, or zero

• Sorting algorithms that need to consider sign differences

Conclusion

The Math.Sign() method in C# provides a simple way to determine the sign of any numeric value, returning -1 for negative, 0 for zero, and +1 for positive numbers. It works with all numeric data types and is commonly used in conditional logic and mathematical operations.