Float

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

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.

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.

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.

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.

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.

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.