Csharp/C Sharp/Data Types/double

Compute the area of a circle

<source lang="csharp"> /* C#: The Complete Reference by Herbert Schildt Publisher: Osborne/McGraw-Hill (March 8, 2002) ISBN: 0072134852

• /

// Compute the area of a circle.

using System;

public class ComputeCircle {

 static void Main() {   
   double radius; 
   double area; 

   radius = 10.0; 
   area = radius * radius * 3.1416; 

   Console.WriteLine("Area is " + area); 
 }   

}

      </source>

converts Fahrenheit to Celsius

<source lang="csharp"> /*

  This program converts Fahrenheit to Celsius. 

  Call this program FtoC.cs. 

• /

using System;

public class FtoC {

 public static void Main() {  
   double f; // holds the temperature in Fahrenheit 
   double c; // holds the temparture in Celsius 

   f = 59.0; // start with 59 degrees Fahrenheit 

   c = 5.0 / 9.0 * (f - 32.0); // convert to Celsius 

   Console.Write(f + " degrees Fahrenheit is "); 
   Console.WriteLine(c + " degrees Celsius."); 
 }  

}

      </source>

double number format: 0:C, 0:D9, 0:E, 0:F3, 0:N, 0:X, 0:x

<source lang="csharp"> using System; using System.Collections.Generic; using System.Text; class Program {

   static void Main(string[] args) {
       Console.WriteLine("C format: {0:C}", 99989.987);
       Console.WriteLine("D9 format: {0:D9}", 99999);
       Console.WriteLine("E format: {0:E}", 99999.76543);
       Console.WriteLine("F3 format: {0:F3}", 99999.9999);
       Console.WriteLine("N format: {0:N}", 99999);
       Console.WriteLine("X format: {0:X}", 99999);
       Console.WriteLine("x format: {0:x}", 99999);
   }

}

</source>

Epsilon, PositiveInfinity, NegativeInfinity, MaxValue, MinValue

<source lang="csharp"> using System; using System.Collections.Generic; using System.Text; class Program {

   static void Main(string[] args) {
       Console.WriteLine("-> double.Epsilon: {0}", double.Epsilon);
       Console.WriteLine("-> double.PositiveInfinity: {0}", double.PositiveInfinity);
       Console.WriteLine("-> double.NegativeInfinity: {0}", double.NegativeInfinity);
       Console.WriteLine("-> double.MaxValue: {0}", double.MaxValue);
       Console.WriteLine("-> double.MinValue: {0}", double.MinValue);
   }

}

</source>

Format double value

<source lang="csharp"> using System; public class NumParsingApp {

   public static void Main(string[] args)
   {
       int i = int.Parse("12345");
       Console.WriteLine("i = {0}", i);
  
       int j = Int32.Parse("12345");
       Console.WriteLine("j = {0}", j);
  
       double d = Double.Parse("1.2345E+6");
       Console.WriteLine("d = {0:F}", d);
  
       string s = i.ToString();
       Console.WriteLine("s = {0}", s);
   }

}

</source>

Implement the Pythagorean Theorem

<source lang="csharp"> /* C#: The Complete Reference by Herbert Schildt Publisher: Osborne/McGraw-Hill (March 8, 2002) ISBN: 0072134852

• /

// Implement the Pythagorean Theorem.

using System;

public class Pythagorean {

 public static void Main() {     
   double s1; 
   double s2; 
   double hypot; 
   string str; 

   Console.WriteLine("Enter length of first side: "); 
   str = Console.ReadLine(); 
   s1 = Double.Parse(str); 

   Console.WriteLine("Enter length of second side: "); 
   str = Console.ReadLine(); 
   s2 = Double.Parse(str); 

   hypot = Math.Sqrt(s1*s1 + s2*s2); 
 
   Console.WriteLine("Hypotenuse is " + hypot); 
 }     

}

      </source>

Talking to Mars: double value calculation

<source lang="csharp"> /* C# A Beginner"s Guide By Schildt Publisher: Osborne McGraw-Hill ISBN: 0072133295

• /

/*

  Project 2-1 

  Talking to Mars 

  Call this file mars.cs 

• /

using System;

public class Mars {

 public static void Main() {    
   double distance; 
   double lightspeed; 
   double delay; 
   double delay_in_min; 

   distance = 34000000; // 34,000,000 miles 
   lightspeed = 186000; // 186,000 per second 

   delay = distance / lightspeed;     

   Console.WriteLine("Time delay when talking to Mars: " + 
                     delay + " seconds."); 
    
   delay_in_min = delay / 60; 

   Console.WriteLine("This is " + delay_in_min + 
                     " minutes."); 
 }    

}

      </source>

the differences between int and double

<source lang="csharp"> /* C#: The Complete Reference by Herbert Schildt Publisher: Osborne/McGraw-Hill (March 8, 2002) ISBN: 0072134852

• /

/*

  This program illustrates the differences 
  between int and double. 

• /

using System;

public class Example3IntDouble {

 public static void Main() {  
   int ivar;     // this declares an int variable 
   double dvar;  // this declares a floating-point variable 

   ivar = 100;   // assign ivar the value 100 
   
   dvar = 100.0; // assign dvar the value 100.0 

   Console.WriteLine("Original value of ivar: " + ivar); 
   Console.WriteLine("Original value of dvar: " + dvar); 

   Console.WriteLine(); // print a blank line 

   // now, divide both by 3 
   ivar = ivar / 3;  
   dvar = dvar / 3.0; 

   Console.WriteLine("ivar after division: " + ivar); 
   Console.WriteLine("dvar after division: " + dvar); 
 }  

}

      </source>