# Double.CompareTo 方法

## 多載

 CompareTo(Double) 比較這個執行個體與雙精確度的浮點數值，並且傳回一個整數，指出這個執行個體的值是小於、等於或大於特定的雙精確度浮點數值。Compares this instance to a specified double-precision floating-point number and returns an integer that indicates whether the value of this instance is less than, equal to, or greater than the value of the specified double-precision floating-point number. CompareTo(Object) 比較這個執行個體與特定物件，並且傳回一個整數，指出這個執行個體的值是小於、等於或大於特定物件的值。Compares this instance to a specified object and returns an integer that indicates whether the value of this instance is less than, equal to, or greater than the value of the specified object.

## CompareTo(Double)

``````public:
virtual int CompareTo(double value);``````
``public int CompareTo (double value);``
``````abstract member CompareTo : double -> int
override this.CompareTo : double -> int``````
``Public Function CompareTo (value As Double) As Integer``

value
Double

#### 傳回

Zero 這個執行個體等於 `value`This instance is equal to `value`. -或--or- 這個執行個體和 `value` 都不會是數字 (NaN)、PositiveInfinityNegativeInfinityBoth this instance and `value` are not a number (NaN), PositiveInfinity, or NegativeInfinity.

### 範例

``````// This example demonstrates the two versions of the
// CompareTo method for several base types.
// The general version takes a parameter of type Object, while the specific
// version takes a type-specific parameter, such as Boolean, Int32, or Double.
using namespace System;

void Show( String^ caption, Object^ var1, Object^ var2, int resultGeneric, int resultNonGeneric )
{
String^ relation;
Console::Write( caption );
if ( resultGeneric == resultNonGeneric )
{
if ( resultGeneric < 0 )
relation = "less than";
else
if ( resultGeneric > 0 )
relation = "greater than";
else
relation = "equal to";
Console::WriteLine( "{0} is {1} {2}", var1, relation, var2 );
}
// The following condition will never occur because the generic and non-generic
// CompareTo methods are equivalent.
else
{
Console::WriteLine( "Generic CompareTo = {0}; non-generic CompareTo = {1}", resultGeneric, resultNonGeneric );
}
}

int main()
{
String^ nl = Environment::NewLine;
String^ msg = "{0}The following is the result of using the generic and non-generic{0}"
"versions of the CompareTo method for several base types:{0}";
Object^ obj; // An Object used to insure CompareTo(Object) is called.

DateTime now = DateTime::Now;

// Time span = 11 days, 22 hours, 33 minutes, 44 seconds
TimeSpan tsX = TimeSpan(11,22,33,44);

// Version = 1.2.333.4
Version^ versX = gcnew Version(  "1.2.333.4" );

// Guid = CA761232-ED42-11CE-BACD-00AA0057B223
Guid guidX = Guid( "{CA761232-ED42-11CE-BACD-00AA0057B223}");
Boolean a1 = true,a2 = true;
Byte b1 = 1,b2 = 1;
Int16 c1 = -2,c2 = 2;
Int32 d1 = 3,d2 = 3;
Int64 e1 = 4,e2 = -4;
Decimal f1 = Decimal(-5.5), f2 = Decimal(5.5);
Single g1 = 6.6f,g2 = 6.6f;
Double h1 = 7.7,h2 = -7.7;
Char i1 = 'A',i2 = 'A';
String^ j1 = "abc", ^j2 = "abc";
DateTime k1 = now,k2 = now;
TimeSpan l1 = tsX,l2 = tsX;
Version^ m1 = versX, ^m2 = gcnew Version(  "2.0" );
Guid n1 = guidX,n2 = guidX;

// The following types are not CLS-compliant.
SByte w1 = 8,w2 = 8;
UInt16 x1 = 9,x2 = 9;
UInt32 y1 = 10,y2 = 10;
UInt64 z1 = 11,z2 = 11;

//
Console::WriteLine( msg, nl );
try
{
Show( "Boolean: ", a1, a2, a1.CompareTo( a2 ), a1.CompareTo( a2 ) );
Show( "Byte:    ", b1, b2, b1.CompareTo( b2 ), b1.CompareTo( b2 ) );
Show( "Int16:   ", c1, c2, c1.CompareTo( c2 ), c1.CompareTo( c2 ) );
Show( "Int32:   ", d1, d2, d1.CompareTo( d2 ), d1.CompareTo( d2 ) );
Show( "Int64:   ", e1, e2, e1.CompareTo( e2 ), e1.CompareTo( e2 ) );
Show( "Decimal: ", f1, f2, f1.CompareTo( f2 ), f1.CompareTo( f2 ) );
Show( "Single:  ", g1, g2, g1.CompareTo( g2 ), g1.CompareTo( g2 ) );
Show( "Double:  ", h1, h2, h1.CompareTo( h2 ), h1.CompareTo( h2 ) );
Show( "Char:    ", i1, i2, i1.CompareTo( i2 ), i1.CompareTo( i2 ) );

// Use an anonymous object to hide the String object.
obj = j2;
Show( "String:  ", j1, j2, j1->CompareTo( j2 ), j1->CompareTo( obj ) );
Show( "DateTime:", k1, k2, k1.CompareTo( k2 ), k1.CompareTo( k2 ) );
Show(  "TimeSpan: ", l1, l2, l1.CompareTo( l2 ), l1.CompareTo( l2 ) );

// Use an anonymous object to hide the Version object.
obj = m2;
Show(  "Version:  ", m1, m2, m1->CompareTo( m2 ), m1->CompareTo( obj ) );
Show(  "Guid:     ", n1, n2, n1.CompareTo( n2 ), n1.CompareTo( n2 ) );

//
Console::WriteLine( "{0}The following types are not CLS-compliant:", nl );
Show( "SByte:   ", w1, w2, w1.CompareTo( w2 ), w1.CompareTo( w2 ) );
Show( "UInt16:  ", x1, x2, x1.CompareTo( x2 ), x1.CompareTo( x2 ) );
Show( "UInt32:  ", y1, y2, y1.CompareTo( y2 ), y1.CompareTo( y2 ) );
Show( "UInt64:  ", z1, z2, z1.CompareTo( z2 ), z1.CompareTo( z2 ) );
}
catch ( Exception^ e )
{
Console::WriteLine( e );
}

}
//     This example displays the following output:
//
//     The following is the result of using the generic and non-generic versions of the
//     CompareTo method for several base types:
//
//     Boolean:  True is equal to True
//     Byte:     1 is equal to 1
//     Int16:    -2 is less than 2
//     Int32:    3 is equal to 3
//     Int64:    4 is greater than -4
//     Decimal:  -5.5 is less than 5.5
//     Single:   6.6 is equal to 6.6
//     Double:   7.7 is greater than -7.7
//     Char:     A is equal to A
//     String:   abc is equal to abc
//     DateTime: 12/1/2003 5:37:46 PM is equal to 12/1/2003 5:37:46 PM
//     TimeSpan: 11.22:33:44 is equal to 11.22:33:44
//     Version:  1.2.333.4 is less than 2.0
//     Guid:     ca761232-ed42-11ce-bacd-00aa0057b223 is equal to ca761232-ed42-11ce-bacd-00
//     aa0057b223
//
//     The following types are not CLS-compliant:
//     SByte:    8 is equal to 8
//     UInt16:   9 is equal to 9
//     UInt32:   10 is equal to 10
//     UInt64:   11 is equal to 11
``````
``````// This example demonstrates the generic and non-generic versions of the
// CompareTo method for several base types.
// The non-generic version takes a parameter of type Object, while the generic
// version takes a type-specific parameter, such as Boolean, Int32, or Double.

using System;

class Sample
{
public static void Main()
{
string    nl = Environment.NewLine;
string    msg = "{0}The following is the result of using the generic and non-generic{0}" +
"versions of the CompareTo method for several base types:{0}";

DateTime  now = DateTime.Now;
// Time span = 11 days, 22 hours, 33 minutes, 44 seconds
TimeSpan  tsX = new TimeSpan(11, 22, 33, 44);
// Version = 1.2.333.4
Version   versX = new Version("1.2.333.4");
// Guid = CA761232-ED42-11CE-BACD-00AA0057B223
Guid      guidX = new Guid("{CA761232-ED42-11CE-BACD-00AA0057B223}");

Boolean  a1 = true,  a2 = true;
Byte     b1 = 1,     b2 = 1;
Int16    c1 = -2,    c2 = 2;
Int32    d1 = 3,     d2 = 3;
Int64    e1 = 4,     e2 = -4;
Decimal  f1 = -5.5m, f2 = 5.5m;
Single   g1 = 6.6f,  g2 = 6.6f;
Double   h1 = 7.7d,  h2 = -7.7d;
Char     i1 = 'A',   i2 = 'A';
String   j1 = "abc", j2 = "abc";
DateTime k1 = now,   k2 = now;
TimeSpan l1 = tsX,   l2 = tsX;
Version  m1 = versX, m2 = new Version("2.0");
Guid     n1 = guidX, n2 = guidX;

// The following types are not CLS-compliant.
SByte    w1 = 8,     w2 = 8;
UInt16   x1 = 9,     x2 = 9;
UInt32   y1 = 10,    y2 = 10;
UInt64   z1 = 11,    z2 = 11;
//
Console.WriteLine(msg, nl);
try
{
// The second and third Show method call parameters are automatically boxed because
// the second and third Show method declaration arguments expect type Object.

Show("Boolean:  ", a1, a2, a1.CompareTo(a2), a1.CompareTo((Object)a2));
Show("Byte:     ", b1, b2, b1.CompareTo(b2), b1.CompareTo((Object)b2));
Show("Int16:    ", c1, c2, c1.CompareTo(c2), c1.CompareTo((Object)c2));
Show("Int32:    ", d1, d2, d1.CompareTo(d2), d1.CompareTo((Object)d2));
Show("Int64:    ", e1, e2, e1.CompareTo(e2), e1.CompareTo((Object)e2));
Show("Decimal:  ", f1, f2, f1.CompareTo(f2), f1.CompareTo((Object)f2));
Show("Single:   ", g1, g2, g1.CompareTo(g2), g1.CompareTo((Object)g2));
Show("Double:   ", h1, h2, h1.CompareTo(h2), h1.CompareTo((Object)h2));
Show("Char:     ", i1, i2, i1.CompareTo(i2), i1.CompareTo((Object)i2));
Show("String:   ", j1, j2, j1.CompareTo(j2), j1.CompareTo((Object)j2));
Show("DateTime: ", k1, k2, k1.CompareTo(k2), k1.CompareTo((Object)k2));
Show("TimeSpan: ", l1, l2, l1.CompareTo(l2), l1.CompareTo((Object)l2));
Show("Version:  ", m1, m2, m1.CompareTo(m2), m1.CompareTo((Object)m2));
Show("Guid:     ", n1, n2, n1.CompareTo(n2), n1.CompareTo((Object)n2));
//
Console.WriteLine("{0}The following types are not CLS-compliant:", nl);
Show("SByte:    ", w1, w2, w1.CompareTo(w2), w1.CompareTo((Object)w2));
Show("UInt16:   ", x1, x2, x1.CompareTo(x2), x1.CompareTo((Object)x2));
Show("UInt32:   ", y1, y2, y1.CompareTo(y2), y1.CompareTo((Object)y2));
Show("UInt64:   ", z1, z2, z1.CompareTo(z2), z1.CompareTo((Object)z2));
}
catch (Exception e)
{
Console.WriteLine(e);
}
}

public static void Show(string caption, Object var1, Object var2,
int resultGeneric, int resultNonGeneric)
{
string relation;

Console.Write(caption);
if (resultGeneric == resultNonGeneric)
{
if      (resultGeneric < 0) relation = "less than";
else if (resultGeneric > 0) relation = "greater than";
else                        relation = "equal to";
Console.WriteLine("{0} is {1} {2}", var1, relation, var2);
}

// The following condition will never occur because the generic and non-generic
// CompareTo methods are equivalent.

else
{
Console.WriteLine("Generic CompareTo = {0}; non-generic CompareTo = {1}",
resultGeneric, resultNonGeneric);
}
}
}
/*
This example produces the following results:

The following is the result of using the generic and non-generic versions of the
CompareTo method for several base types:

Boolean:  True is equal to True
Byte:     1 is equal to 1
Int16:    -2 is less than 2
Int32:    3 is equal to 3
Int64:    4 is greater than -4
Decimal:  -5.5 is less than 5.5
Single:   6.6 is equal to 6.6
Double:   7.7 is greater than -7.7
Char:     A is equal to A
String:   abc is equal to abc
DateTime: 12/1/2003 5:37:46 PM is equal to 12/1/2003 5:37:46 PM
TimeSpan: 11.22:33:44 is equal to 11.22:33:44
Version:  1.2.333.4 is less than 2.0
Guid:     ca761232-ed42-11ce-bacd-00aa0057b223 is equal to ca761232-ed42-11ce-bacd-00
aa0057b223

The following types are not CLS-compliant:
SByte:    8 is equal to 8
UInt16:   9 is equal to 9
UInt32:   10 is equal to 10
UInt64:   11 is equal to 11
*/
``````
``````' This example demonstrates the generic and non-generic versions of the
' CompareTo method for several base types.
' The non-generic version takes a parameter of type Object, while the generic
' version takes a type-specific parameter, such as Boolean, Int32, or Double.

Class Sample
Public Shared Sub Main()
Dim nl As String = Environment.NewLine
Dim msg As String = _
"{0}The following is the result of using the generic and non-generic{0}" & _
"versions of the CompareTo method for several base types:{0}"

Dim now As DateTime = DateTime.Now
' Time span = 11 days, 22 hours, 33 minutes, 44 seconds
Dim tsX As New TimeSpan(11, 22, 33, 44)
' Version = 1.2.333.4
Dim versX As New Version("1.2.333.4")
' Guid = CA761232-ED42-11CE-BACD-00AA0057B223
Dim guidX As New Guid("{CA761232-ED42-11CE-BACD-00AA0057B223}")

Dim a1 As [Boolean] = True,    a2 As [Boolean] = True
Dim b1 As [Byte] = 1,          b2 As [Byte] = 1
Dim c1 As Int16 = -2,          c2 As Int16 = 2
Dim d1 As Int32 = 3,           d2 As Int32 = 3
Dim e1 As Int64 = 4,           e2 As Int64 = -4
Dim f1 As [Decimal] = -5.5D,   f2 As [Decimal] = 5.5D
Dim g1 As [Single] = 6.6F,     g2 As [Single] = 6.6F
Dim h1 As [Double] = 7.7,      h2 As [Double] = -7.7
Dim i1 As [Char] = "A"c,       i2 As [Char] = "A"c
Dim j1 As String = "abc",      j2 As String = "abc"
Dim k1 As DateTime = now,      k2 As DateTime = now
Dim l1 As TimeSpan = tsX,      l2 As TimeSpan = tsX
Dim m1 As Version = versX,     m2 As New Version("2.0")
Dim n1 As Guid = guidX,        n2 As Guid = guidX

' The following types are not CLS-compliant.
' SByte, UInt16, UInt32, UInt64

Console.WriteLine(msg, nl)
Try
' The second and third Show method call parameters are automatically boxed because
' the second and third Show method declaration arguments expect type Object.

Show("Boolean:  ", a1, a2, a1.CompareTo(a2), a1.CompareTo(CObj(a2)))
Show("Byte:     ", b1, b2, b1.CompareTo(b2), b1.CompareTo(CObj(b2)))
Show("Int16:    ", c1, c2, c1.CompareTo(c2), c1.CompareTo(CObj(c2)))
Show("Int32:    ", d1, d2, d1.CompareTo(d2), d1.CompareTo(CObj(d2)))
Show("Int64:    ", e1, e2, e1.CompareTo(e2), e1.CompareTo(CObj(e2)))
Show("Decimal:  ", f1, f2, f1.CompareTo(f2), f1.CompareTo(CObj(f2)))
Show("Single:   ", g1, g2, g1.CompareTo(g2), g1.CompareTo(CObj(g2)))
Show("Double:   ", h1, h2, h1.CompareTo(h2), h1.CompareTo(CObj(h2)))
Show("Char:     ", i1, i2, i1.CompareTo(i2), i1.CompareTo(CObj(i2)))
Show("String:   ", j1, j2, j1.CompareTo(j2), j1.CompareTo(CObj(j2)))
Show("DateTime: ", k1, k2, k1.CompareTo(k2), k1.CompareTo(CObj(k2)))
Show("TimeSpan: ", l1, l2, l1.CompareTo(l2), l1.CompareTo(CObj(l2)))
Show("Version:  ", m1, m2, m1.CompareTo(m2), m1.CompareTo(CObj(m2)))
Show("Guid:     ", n1, n2, n1.CompareTo(n2), n1.CompareTo(CObj(n2)))
'
Console.WriteLine("{0}The following types are not CLS-compliant:", nl)
Console.WriteLine("SByte, UInt16, UInt32, UInt64")

Catch e As Exception
Console.WriteLine(e)
End Try
End Sub

Public Shared Sub Show(caption As String, var1 As [Object], var2 As [Object], _
resultGeneric As Integer, resultNonGeneric As Integer)
Dim relation As String

Console.Write(caption)
If resultGeneric = resultNonGeneric Then
If resultGeneric < 0 Then
relation = "less than"
ElseIf resultGeneric > 0 Then
relation = "greater than"
Else
relation = "equal to"
End If
Console.WriteLine("{0} is {1} {2}", var1, relation, var2)

' The following condition will never occur because the generic and non-generic
' CompareTo methods are equivalent.

Else
Console.WriteLine("Generic CompareTo = {0}; non-generic CompareTo = {1}", _
resultGeneric, resultNonGeneric)
End If
End Sub
End Class
'
'This example produces the following results:
'
'The following is the result of using the generic and non-generic versions of the
'CompareTo method for several base types:
'
'Boolean:  True is equal to True
'Byte:     1 is equal to 1
'Int16:    -2 is less than 2
'Int32:    3 is equal to 3
'Int64:    4 is greater than -4
'Decimal:  -5.5 is less than 5.5
'Single:   6.6 is equal to 6.6
'Double:   7.7 is greater than -7.7
'Char:     A is equal to A
'String:   abc is equal to abc
'DateTime: 12/1/2003 5:37:46 PM is equal to 12/1/2003 5:37:46 PM
'TimeSpan: 11.22:33:44 is equal to 11.22:33:44
'Version:  1.2.333.4 is less than 2.0
'Guid:     ca761232-ed42-11ce-bacd-00aa0057b223 is equal to ca761232-ed42-11ce-bacd-00
'aa0057b223
'
'The following types are not CLS-compliant:
'SByte, UInt16, UInt32, UInt64
'
``````

### 備註

``````using System;

public class Example
{
public static void Main()
{
double value1 = 6.185;
double value2 = value1 * .1 / .1;
Console.WriteLine("Comparing {0} and {1}: {2}\n",
value1, value2, value1.CompareTo(value2));
Console.WriteLine("Comparing {0:R} and {1:R}: {2}",
value1, value2, value1.CompareTo(value2));
}
}
// The example displays the following output:
//       Comparing 6.185 and 6.185: -1
//
//       Comparing 6.185 and 6.1850000000000005: -1
``````
``````Module Example
Public Sub Main()
Dim value1 As Double = 6.185
Dim value2 As Double = value1 * .1 / .1
Console.WriteLine("Comparing {0} and {1}: {2}",
value1, value2, value1.CompareTo(value2))
Console.WriteLine()
Console.WriteLine("Comparing {0:R} and {1:R}: {2}",
value1, value2, value1.CompareTo(value2))
End Sub
End Module
' The example displays the following output:
'       Comparing 6.185 and 6.185: -1
'
'       Comparing 6.185 and 6.1850000000000005: -1
``````

## CompareTo(Object)

``````public:
virtual int CompareTo(System::Object ^ value);``````
``public int CompareTo (object value);``
``````abstract member CompareTo : obj -> int
override this.CompareTo : obj -> int``````
``Public Function CompareTo (value As Object) As Integer``

value
Object

#### 傳回

Value 描述Description

Zero 這個執行個體等於 `value`This instance is equal to `value`. -或--or- 這個執行個體和 `value` 都是 `Double.NaN`PositiveInfinityNegativeInfinityThis instance and `value` are both `Double.NaN`, PositiveInfinity, or NegativeInfinity

#### 例外狀況

`value` 不是 Double`value` is not a Double.

### 範例

``````obj1 = (Double)450;
if ( a.CompareTo( obj1 ) < 0 )
{
Console::WriteLine( "{0} is less than {1}.", a, obj1 );
}

if ( a.CompareTo( obj1 ) > 0 )
{
Console::WriteLine( "{0} is greater than {1}.", a, obj1 );
}

if ( a.CompareTo( obj1 ) == 0 )
{
Console::WriteLine( "{0} equals {1}.", a, obj1 );
}
``````
``````obj1 = (Double)450;

if (a.CompareTo(obj1) < 0)
Console.WriteLine("{0} is less than {1}.", a.ToString(), obj1.ToString());

if (a.CompareTo(obj1) > 0)
Console.WriteLine("{0} is greater than {1}.", a.ToString(), obj1.ToString());

if (a.CompareTo(obj1) == 0)
Console.WriteLine("{0} equals {1}.", a.ToString(), obj1.ToString());
``````
``````Obj1 = CType(450, Double)

If A.CompareTo(Obj1) < 0 Then
Console.WriteLine(A.ToString() + " is less than " + Obj1.ToString() + ".")
End If

If (A.CompareTo(Obj1) > 0) Then
Console.WriteLine(A.ToString() + " is greater than " + Obj1.ToString() + ".")
End If

If (A.CompareTo(Obj1) = 0) Then
Console.WriteLine(A.ToString() + " equals " + Obj1.ToString() + ".")
End If
``````

### 備註

`value` 參數必須 `null``Double`的實例。否則，就會擲回例外狀況。The `value` parameter must be `null` or an instance of `Double`; otherwise, an exception is thrown. 任何 Double的實例（不論其值為何）都會視為大於 `null`Any instance of Double, regardless of its value, is considered greater than `null`.

``````using System;

public class Example
{
public static void Main()
{
double value1 = 6.185;
object value2 = value1 * .1 / .1;
Console.WriteLine("Comparing {0} and {1}: {2}\n",
value1, value2, value1.CompareTo(value2));
Console.WriteLine("Comparing {0:R} and {1:R}: {2}",
value1, value2, value1.CompareTo(value2));
}
}
// The example displays the following output:
//       Comparing 6.185 and 6.185: -1
//
//       Comparing 6.185 and 6.1850000000000005: -1
``````
``````Module Example
Public Sub Main()
Dim value1 As Double = 6.185
Dim value2 As Object = value1 * .1 / .1
Console.WriteLine("Comparing {0} and {1}: {2}",
value1, value2, value1.CompareTo(value2))
Console.WriteLine()
Console.WriteLine("Comparing {0:R} and {1:R}: {2}",
value1, value2, value1.CompareTo(value2))
End Sub
End Module
' The example displays the following output:
'       Comparing 6.185 and 6.185: -1
'
'       Comparing 6.185 and 6.1850000000000005: -1
``````