double int Math.Pow Math.Round Multiply out OverflowException

Math

This is a class in the System namespace. The .NET Framework provides many built-in mathematical methods. These are easier to use than custom expressions.

Math methods

These methods are tested and easy to access. This page contains information on some less-common math methods like Sign and DivRem.

Sign

Is a number positive or negative? The Math.Sign method will help you determine this. Math.Sign accepts many numeric types as arguments. It returns one of three values: -1, 0 or 1.

Info The result -1 means negative. Zero means the number is zero. And 1 means it is positive.

Next This program demonstrates the Math.Sign method with ints and doubles as arguments.

Tip Sign is implemented with branch statements that test the parameter against zero.

using System;

int a = Math.Sign(-5);
int b = Math.Sign(5);
int c = Math.Sign(0);

Console.WriteLine(a);
Console.WriteLine(b);
Console.WriteLine(c);

a = Math.Sign(-5.5);
b = Math.Sign(5.5);

Console.WriteLine(a);
Console.WriteLine(b);-1
1
0
-1
1

Log

Here we compute the logarithms of some known numbers. The logarithm of 1 with base "e" is always zero—the method matches this result.

And The logarithm of 1000 with base 10 is always 3. This is because 10 to the power of 3 is 1000.

Finally You can duplicate the effects of Log10 with Log by passing 10 as the second argument.

using System;

double a = Math.Log(1);
Console.WriteLine(a);

// Ten to the power of 3 is 1000.
double b = Math.Log10(1000);
Console.WriteLine(b);

double c = Math.Log(1000, 10);
Console.WriteLine(c);0
3
3

Exp

Math.Exp is the exponential function. To apply the exponential function, we either use Math.Pow to raise E to a specified power, or call Math.Exp with the exponent as an argument.

Here This program calls the Math.Exp method and then calls the Math.Pow method such that they have equivalent results.

Note The Math.Exp always uses Math.E (e) as the specified number. The results of these two method calls are the same.

using System;

// Compute e ^ 2.
double a = Math.Exp(2);
double b = Math.Pow(Math.E, 2);

// Write results.
Console.WriteLine(a);
Console.WriteLine(b);7.38905609893065
7.38905609893065

`IEEERemainder`

This is similar to a modulo expression, but the results are different when we use a larger second number. In many cases, the modulo operator returns the same result.

Part 1 The IEEERemainder method returns a remainder of 1 for the arguments 4, 3. This is the same result as the modulo expression.

Part 2 With the arguments 3 and 4, it returns a remainder of -1. The modulo expression meanwhile returns the value 3.

Here We see that for IEEERemainder, two positive numbers can have a negative remainder.

using System;

// Part 1: use larger first number.
double a = Math.IEEERemainder(4, 3);
Console.WriteLine("Part 1");
Console.WriteLine(a);
Console.WriteLine(4 % 3);

// Part 2: use smaller first number.
double b = Math.IEEERemainder(3, 4);
Console.WriteLine("Part 2");
Console.WriteLine(b);
Console.WriteLine(3 % 4);Part 1
1
1
Part 2
-1
3

`BigMul`

This multiplies two integers. With regular multiplication, as with the star operator, the result may overflow. BigMul avoids this problem. It returns a long.

Here This program's goal is to multiply the int.MaxValue value (2147483647) by itself. If we call Math.BigMul, the result will be correct.

Tip You should probably use BigMul anywhere you are multiplying large integers.

using System;

// Call BigMul.
long product1 = Math.BigMul(int.MaxValue, int.MaxValue);
// Use multiplication operator.
long product2 = unchecked(int.MaxValue * int.MaxValue);

// Display values.
Console.WriteLine(product1);
Console.WriteLine(product2);4611686014132420609
1

`DivRem`

Math.DivRem divides two numbers and returns the remainder. With the division operator we do not get the remainder in a separate variable. But with DivRem we get both parts.

Here This program divides the value 1000 by the value 300. Because the 300 can go into the 1000 three times, you get the result of 3.

However There is 100 left over. This is returned by the out parameter in the Math.DivRem method.

Tip The out parameter in the DivRem method is always assigned when DivRem returns. It will be ready to use.

using System;

const int a = 1000;
const int b = 300;
int result;

int quotient = Math.DivRem(a, b, out result);

Console.WriteLine(quotient);
Console.WriteLine(result);3
100

E constant

To access Math.E, use "System.Math.E" or include the using System directive at the top. The constant is encoded as a Float64 type in the Framework. Float64 has a 64-bit data space.

using System;

double e = Math.E; // Get E constant
Console.WriteLine("--- Math.E ---");
Console.WriteLine(e); // Write E constant--- Math.E ---
2.71828182845905

Cos, sin, tan

This example calls Acos, Cos, Cosh, Asin, Sin, Sinh, Atan, Tan and Tanh. All of these methods receive arguments in units of radians represented by the double type.

Next In this program, the C# compiler implicitly converts the integer arguments into double arguments.

using System;

Console.WriteLine(Math.Acos(0)); // Inverse cosine
Console.WriteLine(Math.Cos(2)); // Cosine
Console.WriteLine(Math.Cosh(5)); // Hyperbolic cosine

Console.WriteLine(Math.Asin(0.2)); // Inverse sine
Console.WriteLine(Math.Sin(2)); // Sine
Console.WriteLine(Math.Sinh(-5)); // Hyperbolic sine

Console.WriteLine(Math.Atan(-5)); // Inverse tangent
Console.WriteLine(Math.Tan(1)); // Tangent
Console.WriteLine(Math.Tanh(0.1)); // Hyperbolic tangent  1.5707963267949
 -0.416146836547142
 74.2099485247878
  0.201357920790331
  0.909297426825682
-74.2032105777888
 -1.37340076694502
  1.5574077246549
  0.0996679946249558

Summary

Instead of implementing these functions yourself, I suggest using the Math type. It has many public static methods. You may be able to improve the quality of your code.