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float (C# Reference)

The float keyword signifies a simple type that stores 32-bit floating-point values. The following table shows the precision and approximate range for the float type.

Type

Approximate range

Precision

.NET Framework type

float

-3.4 × 1038to +3.4 × 1038

7 digits

System.Single

By default, a real numeric literal on the right side of the assignment operator is treated as double. Therefore, to initialize a float variable, use the suffix f or F, as in the following example:

float x = 3.5F;

If you do not use the suffix in the previous declaration, you will get a compilation error because you are trying to store a double value into a float variable.

You can mix numeric integral types and floating-point types in an expression. In this case, the integral types are converted to floating-point types. The evaluation of the expression is performed according to the following rules:

  • If one of the floating-point types is double, the expression evaluates to double or bool in relational or Boolean expressions.

  • If there is no double type in the expression, the expression evaluates to float or bool in relational or Boolean expressions.

A floating-point expression can contain the following sets of values:

  • Positive and negative zero

  • Positive and negative infinity

  • Not-a-Number value (NaN)

  • The finite set of nonzero values

For more information about these values, see IEEE Standard for Binary Floating-Point Arithmetic, available on the IEEE Web site.

In the following example, an int, a short, and a float are included in a mathematical expression giving a float result. (Remember that float is an alias for the System.Single type.) Notice that there is no double in the expression.

class FloatTest 
{
    static void Main() 
    {
        int x = 3;
        float y = 4.5f;
        short z = 5;
        var result = x * y / z;
        Console.WriteLine("The result is {0}", result);
        Type type = result.GetType();
        Console.WriteLine("result is of type {0}", type.ToString());
    }
}
/* Output: 
  The result is 2.7
  result is of type System.Single //'float' is alias for 'Single'
 */

For more information, see the following sections in the C# Language Specification:

  • 4.1.6 Floating Point Types

  • 6.2.1 Explicit Numeric Conversions

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