Math.PI / Math.E / Random
Classes for mathematical constants and random number generation. The Math class provides mathematical constants and functions, while the Random class generates random numbers.
Syntax
// Referencing mathematical constants double pi = Math.PI; double e = Math.E; // Creating a Random instance and getting random values Random rng = new Random(); int n = rng.Next(min, max); // An integer >= min and < max double d = rng.NextDouble(); // A floating-point number >= 0.0 and < 1.0
Member List
| Member | Description |
|---|---|
| Math.PI | A constant representing the ratio of a circle's circumference to its diameter, π (3.141592653589793). |
| Math.E | A constant representing the base of the natural logarithm, e (2.718281828459045). |
| Math.Abs(x) | Returns the absolute value of a number. |
| Math.Sqrt(x) | Returns the square root of a number. |
| Math.Pow(x, y) | Returns x raised to the power of y. |
| Math.Round(x, n) | Returns the value rounded to n decimal places (banker's rounding). |
| Math.Floor(x) | Returns the largest integer less than or equal to x (floor function). |
| Math.Ceiling(x) | Returns the smallest integer greater than or equal to x (ceiling function). |
| Math.Max(a, b) | Returns the larger of two values. |
| Math.Min(a, b) | Returns the smaller of two values. |
| Random.Next(min, max) | Returns a random integer that is >= min and < max. |
| Random.NextDouble() | Returns a random floating-point number that is >= 0.0 and < 1.0. |
| Random.NextBytes(buf) | Fills a byte array with random values. |
| Random.Shared | A thread-safe shared instance available in .NET 6 and later. |
Sample Code
using System;
// Referencing mathematical constants
Console.WriteLine($"π = {Math.PI}"); // 3.141592653589793
Console.WriteLine($"e = {Math.E}"); // 2.718281828459045
// Calculate the area of a circle (π × r²).
double radius = 5.0;
double area = Math.PI * Math.Pow(radius, 2);
Console.WriteLine($"Area of circle with radius {radius}: {area:F4}"); // 78.5398
// Basic usage of math functions
Console.WriteLine(Math.Sqrt(16)); // 4 — square root
Console.WriteLine(Math.Abs(-42)); // 42 — absolute value
Console.WriteLine(Math.Max(10, 20)); // 20 — maximum value
Console.WriteLine(Math.Round(3.456, 2)); // 3.46 — rounded
// Generate random numbers with Random (no seed means truly random).
Random rng = new Random();
Console.WriteLine(rng.Next(1, 7)); // A dice roll from 1 to 6
Console.WriteLine(rng.NextDouble()); // A value >= 0.0 and < 1.0
// Passing a fixed seed produces the same sequence every time (useful for testing).
Random seeded = new Random(42);
Console.WriteLine(seeded.Next(1, 101)); // Always the same value
// In .NET 6 and later, use Random.Shared for thread-safe access.
int dice = Random.Shared.Next(1, 7);
Console.WriteLine($"Dice: {dice}");
Notes
The Math class is a static class and cannot be instantiated. You reference its constants directly, such as Math.PI and Math.E.
The Random class can generate a reproducible sequence of random numbers by passing a seed (an integer) to its constructor, which makes it useful in test code and learning materials. Sharing a single Random instance across multiple threads in a multithreaded environment can cause race conditions. In .NET 6 and later, use Random.Shared to access a thread-safe shared instance.
Random numbers are also commonly combined with asynchronous operations such as Task.Run() / Task.Delay(). For more on numeric operations, see Enumerable.Aggregate().
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