Working with Math Routines in C#

Basic math operators—such as plus, minus, and modulus—can get you only so far. It is only a matter of time before you find that you need more robust math routines. C# has access to a set of math routines within the base classes. These are available from within the System.Math namespace. Table 1 presents a number of the math methods available.

The Math class is sealed. A sealed class cannot be used for inheritance. Additionally, all the classes and data members are static, so you can't create an object of type Math. Instead, you use the members and methods with the class name.

Table 1: Math Routines in the Math Class

The Math class also includes two constants: PI and E. PI returns the value of [PI] as 3.14159265358979323846. The E data member returns the value of the logarithmic base, 2.7182818284590452354.

Most of the math methods in Table 1 are easy to understand. Listing 1 presents a couple of the routines in use.

Listing 1: MathApp.cs — Using Some of the Math Routines

 1:  //  MathApp.cs - Using a Math routine
 2:  //-----------------------------------------------
 3:  using System;
 4:  
 5:  class MathApp
 6:  {
 7:     public static void Main()
 8:     {
 9:        int val2;
10:        char disp;
11:  
12:        for (double ctr = 0.0; ctr <= 10; ctr += .2)
13:        {
14:           val2 = (int) Math.Round( ( 10 * Math.Sin(ctr))) ;
15:           for( int ctr2 = -10; ctr2 <= 10; ctr2++ )
16:           {
17:              if (ctr2 == val2)
18:                 disp = 'X';
19:              else
20:                 disp = ' ';
21:  
22:              Console.Write("{0}", disp);
23:           }
24:           Console.WriteLine(" ");
25:        }
26:     }
27:  }

The following is the output:

          X           
            X         
              X       
                X     
                 X    
                  X   
                   X  
                    X 
                    X 
                    X 
                   X  
                  X   
                 X    
               X      
             X        
           X          
         X            
       X              
      X               
    X                 
  X                   
 X                    
X                     
X                     
X                     
X                     
 X                    
  X                   
    X                 
     X                
       X              
         X            
           X          
             X        
               X      
                 X    
                  X   
                   X  
                    X 
                    X 
                    X 
                   X  
                   X  
                 X    
                X     
              X       
            X         
          X           
        X             
      X               
     X                

This listing maps out the Sin method. A for statement in Lines 12 to 25 loops through double values, incrementing them by .2 each iteration. The sine of this value is obtained using the Math.Sin method in Line 14. The sine is a value from 1.0 to 1.0. To make the display easier, this value is converted to a value from 10 to 10. This conversion is done by multiplying the returned sine value by 10 and then rounding the value with the Math.Round method.

The result of doing the multiplication and rounding is that val2 is a value from 10 to 10. A for loop in Line 15 displays a single line of characters. This line of characters is spaces, with the exception of the character in the position equal to val2. Line 24 prints another space to start a new line. The result of this work is a rough display of a sine curve.

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