Array Console.WriteLine double int Math.Abs Numeric Suffix Single, Double ToString typeof

Float

This type represents a floating-point number. The C# language provides this type as a single-precision floating point number representation.

Float details

Float is less precise than a double. It occupies four bytes and is no larger than an int. Float can help maintain compatibility with other programs.

Suffixes

You will need to use the character suffix "f" or "F" on constants you want to be treated as float values. If you don't specify "f" or "F", you will get a compile-time error.

Next This program shows how to specify floats with "f" or "F". It is often preferred to use the uppercase F to reduce confusion.

using System;

float val1 = 1.001f; // Lowercase f suffix.
float val2 = 1.002F; // Uppercase F suffix.

Console.WriteLine(val1);
Console.WriteLine(val2);1.001
1.002

Test `float`

You can convert floats to strings, either with ToString or through Console.WriteLine. You can use negative floating point numbers.

Detail You can use the == equality operator on floats, and other arithmetic operators.

Info The expression typeof(float) in the program, as well as the GetType method, both return the System.Single type.

Detail The C# language aliases the float keyword to System.Single so they are precisely equivalent.

Detail The memory usage of floats in the C# language is four bytes per float, which is the same as the int type.

using System;

// Use float type.
float number = 1.5F;
Console.WriteLine(number);
// Set to negative value.
number = -1.001F;
Console.WriteLine(number);
Console.WriteLine(number == -1.001F); // Use == operator
Console.WriteLine(number + 200); // Use + operator
Console.WriteLine(number.GetType());
Console.WriteLine(typeof(float));
Console.WriteLine(float.MinValue.ToString("0"));
Console.WriteLine(float.MaxValue.ToString("0"));

// Find the memory usage for a float value.
long bytes1 = GC.GetTotalMemory(false);
float[] array = new float[1000 * 1000];
array[0] = 1;
long bytes2 = GC.GetTotalMemory(false);
Console.WriteLine("{0} bytes per float", ((bytes2 - bytes1) / (1000000)));1.5
-1.001
True
198.999
System.Single
System.Single
-340282300000000000000000000000000000000
340282300000000000000000000000000000000
4 bytes per float

Constant fields

This program shows the float.Epsilon constant, which is the smallest float value greater than zero. The NaN constant represents not a number.

And The NegativeInfinity and PositiveInfinity constants are tested with float.IsNegativeInfinity and float.IsPositiveInfinity.

using System;

Console.WriteLine(float.Epsilon);
Console.WriteLine(float.NaN);
Console.WriteLine(float.NegativeInfinity);
Console.WriteLine(float.PositiveInfinity);1.401298E-45
NaN
-Infinity
Infinity

Epsilon

One major problem with comparing two float values is that they may be almost, but not exactly, equal. Your program probably wants to consider the two values equal.

And This can be solved with an epsilon test. The float.Epsilon constant is the smallest possible float value.

Detail We take the absolute value of the difference between the two values, and see if the difference is less than float.Epsilon.

Discussion

Typically, if you need to use floating point numbers, using the double type instead is a better choice because it has more precision and is probably more common.

However The double type uses more memory than the float type. In a large array this difference becomes relevant.

Detail Using a float instead of a double can be beneficial if you are sure the loss of precision is immaterial.

Also It is best to match the types closely to existing software to alleviate inconsistencies between different code bases.

Summary

Float is often used for compatibility issues when you need to represent floating-point numbers. Double is usually better for storing large numbers with decimals.