Double.CompareTo Double.CompareTo Double.CompareTo Double.CompareTo Method

定義

このインスタンスと指定したオブジェクトまたは Double オブジェクトを比較し、このインスタンスの値が指定したオブジェクトまたは Double オブジェクトの値よりも小さいか、同じか、または大きいかを示す整数を返します。Compares this instance to a specified object or Double 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 or Double object.

オーバーロード

CompareTo(Double) CompareTo(Double) CompareTo(Double) CompareTo(Double)

このインスタンスと指定した倍精度浮動小数点数を比較し、このインスタンスの値が指定した倍精度浮動小数点数の値よりも小さいか、同じか、または大きいかを示す整数を返します。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) CompareTo(Object) CompareTo(Object) CompareTo(Object)

このインスタンスと指定したオブジェクトを比較し、このインスタンスの値が指定したオブジェクトの値よりも小さいか、同じか、または大きいかを示す整数を返します。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) CompareTo(Double) CompareTo(Double) CompareTo(Double)

このインスタンスと指定した倍精度浮動小数点数を比較し、このインスタンスの値が指定した倍精度浮動小数点数の値よりも小さいか、同じか、または大きいかを示す整数を返します。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.

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

パラメーター

value
Double Double Double Double

比較対象の倍精度浮動小数点数。A double-precision floating-point number to compare.

戻り値

このインスタンスと value の相対値を示す符号付き数値。A signed number indicating the relative values of this instance and value.

戻り値Return Value 説明Description
0 より小さい値Less than zero このインスタンスは value よりも小さくなっています。This instance is less than value. または-or- このインスタンスは非数 (NaN) で、value は数値です。This instance is not a number (NaN) and value is a number.
0Zero このインスタンスは value と等価です。This instance is equal to value. または-or- このインスタンスと value は、どちらも非数 (NaN)、PositiveInfinity、または NegativeInfinity です。Both this instance and value are not a number (NaN), PositiveInfinity, or NegativeInfinity.
0 より大きい値Greater than zero このインスタンスは value よりも大きくなっています。This instance is greater than value. または-or- このインスタンスは数値で、value は非数 (NaN) です。This instance is a number and value is not a number (NaN).

実装

次のコード例に示しますジェネリックと非ジェネリック バージョンのCompareToいくつかの値と参照型のメソッド。The following code example demonstrates generic and nongeneric versions of the CompareTo method for several value and reference types.

// 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.

Imports System

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 'Main
   
   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 'Show
End Class 'Sample
'
'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
'

注釈

値は等しいと見なされるのと同じである必要があります。Values must be identical to be considered equal. 浮動小数点値は、複数の数値演算に依存する場合に特に有効桁数が失われると、最小有効数字以外とほぼ同じにするには、その値には一般的です。Particularly when floating-point values depend on multiple mathematical operations, it is common for them to lose precision and for their values to be nearly identical except for their least significant digits. この戻り値のため、CompareToもメソッドがこの驚くべき見える可能性があります。Because of this, the return value of the CompareTo method at times may seem surprising. など、同じ値で除算の後に特定の値で乗算は、元の値を生成する必要があります。For example, multiplication by a particular value followed by division by the same value should produce the original value. 次の例では、ただし、計算された値に反する元の値より大きい値を指定します。In the following example, however, the computed value turns out to be greater than the original value. "R"を使用して 2 つの値のすべての有効桁数を示す標準数値書式指定文字列計算値が、その有効桁数の元の値と異なることを示します。Showing all significant digits of the two values by using the "R" standard numeric format string indicates that the computed value differs from the original value in its least significant digits. このような比較を処理する方法の詳細については、「解説」を参照してください、Equals(Double)メソッド。For information on handling such comparisons, see the Remarks section of the Equals(Double) method.

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

このメソッドを実装、System.IComparable<T>インターフェイスを実行よりも若干優れています、Double.CompareToメソッドに変換することはありませんので、valueオブジェクトに対するパラメーター。This method implements the System.IComparable<T> interface and performs slightly better than the Double.CompareTo method because it does not have to convert the value parameter to an object.

値があるオブジェクトがNaN値が別のオブジェクトと等しくないと見なされますNaN(自体であっても、)、IComparable<T>インターフェイスである必要がありますA.CompareTo(A)0 を返します。Note that, although an object whose value is NaN is not considered equal to another object whose value is NaN (even itself), the IComparable<T> interface requires that A.CompareTo(A) return zero.

拡大変換Widening Conversions

によって、プログラミング言語をコードにことができる場合があります、CompareToメソッドのパラメーターの型のビット数が少ないが、範囲が狭いインスタンス型よりもします。Depending on your programming language, it might be possible to code a CompareTo method where the parameter type has fewer bits (is narrower) than the instance type. 一部のプログラミング言語のインスタンスとビット数の型としてパラメーターを表す暗黙の拡大変換を実行するため、可能です。This is possible because some programming languages perform an implicit widening conversion that represents the parameter as a type with as many bits as the instance.

たとえば、インスタンスの型がDoubleパラメーターの型とInt32します。For example, suppose the instance type is Double and the parameter type is Int32. Microsoft c# コンパイラはパラメーターの値を表す命令を生成、Doubleオブジェクト、し、生成、Double.CompareTo(Double)比較インスタンスの値とパラメーターの形式を拡張するメソッド。The Microsoft C# compiler generates instructions to represent the value of the parameter as a Double object, then generates a Double.CompareTo(Double) method that compares the values of the instance and the widened representation of the parameter.

コンパイラが数値型の暗黙の拡大変換を実行するプログラミング言語のドキュメントを参照してください。Consult your programming language's documentation to determine if its compiler performs implicit widening conversions of numeric types. 詳細については、次を参照してください。、型変換の表トピック。For more information, see the Type Conversion Tables topic.

比較の有効桁数Precision in Comparisons

文書化されている有効桁数を超える浮動小数点数の有効桁数は、実装と .NET Framework のバージョンに固有です。The precision of floating-point numbers beyond the documented precision is specific to the implementation and version of the .NET Framework. その結果、2 つの数値の比較は、数値の内部表現の有効桁数が変わる可能性がある .NET Framework のバージョン間変更可能性があります。Consequently, a comparison of two particular numbers might change between versions of the .NET Framework because the precision of the numbers' internal representation might change.

こちらもご覧ください

CompareTo(Object) CompareTo(Object) CompareTo(Object) CompareTo(Object)

このインスタンスと指定したオブジェクトを比較し、このインスタンスの値が指定したオブジェクトの値よりも小さいか、同じか、または大きいかを示す整数を返します。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.

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

パラメーター

value
Object Object Object Object

比較対象のオブジェクト、または nullAn object to compare, or null.

戻り値

このインスタンスと value の相対値を示す符号付き数値。A signed number indicating the relative values of this instance and value.

[値]Value 説明Description
負の整数A negative integer このインスタンスは value よりも小さくなっています。This instance is less than value. または-or- このインスタンスは非数 (NaN) で、value は数値です。This instance is not a number (NaN) and value is a number.
0Zero このインスタンスは value と等価です。This instance is equal to value. または-or- このインスタンスと value は、どちらも Double.NaNPositiveInfinity、または NegativeInfinity です。This instance and value are both Double.NaN, PositiveInfinity, or NegativeInfinity
正の整数A positive integer このインスタンスは value よりも大きくなっています。This instance is greater than value. または-or- このインスタンスは数値で、value は非数 (NaN) です。This instance is a number and value is not a number (NaN). または-or- valuenullです。value is null.

実装

例外

valueDouble ではありません。value is not a Double.

次のコード例は、の使用を示しています。CompareToのコンテキストでDoubleします。The following code example illustrates the use of CompareTo in the context of Double.

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

注釈

valueパラメーターである必要がありますnullのインスタンスまたはDouble、それ以外の例外がスローされます。The value parameter must be null or an instance of Double; otherwise, an exception is thrown. 任意のインスタンスのDouble、その値に関係なくと見なされますより大きいnullします。Any instance of Double, regardless of its value, is considered greater than null.

値は等しいと見なされるのと同じである必要があります。Values must be identical to be considered equal. 浮動小数点値は、複数の数値演算に依存する場合に特に有効桁数が失われると、最小有効数字以外とほぼ同じにするには、その値には一般的です。Particularly when floating-point values depend on multiple mathematical operations, it is common for them to lose precision and for their values to be nearly identical except for their least significant digits. この戻り値のため、CompareToもメソッドがこの驚くべき見える可能性があります。Because of this, the return value of the CompareTo method at times may seem surprising. など、同じ値で除算の後に特定の値で乗算は、元の値を生成する必要があります。For example, multiplication by a particular value followed by division by the same value should produce the original value. 次の例では、ただし、計算された値に反する元の値より大きい値を指定します。In the following example, however, the computed value turns out to be greater than the original value. "R"を使用して 2 つの値のすべての有効桁数を示す標準数値書式指定文字列計算値が、その有効桁数の元の値と異なることを示します。Showing all significant digits of the two values by using the "R" standard numeric format string indicates that the computed value differs from the original value in its least significant digits. このような比較を処理する方法の詳細については、「解説」を参照してください、Equals(Double)メソッド。For information on handling such comparisons, see the Remarks section of the Equals(Double) method.

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

このメソッドがサポートするために実装されて、IComparableインターフェイス。This method is implemented to support the IComparable interface. NaN別にするとは見なされませんNaN(自体であっても、)、IComparableインターフェイスである必要がありますA.CompareTo(A)0 を返します。Note that, although a NaN is not considered to be equal to another NaN (even itself), the IComparable interface requires that A.CompareTo(A) return zero.

比較の有効桁数Precision in Comparisons

文書化されている有効桁数を超える浮動小数点数の有効桁数は、実装と .NET Framework のバージョンに固有です。The precision of floating-point numbers beyond the documented precision is specific to the implementation and version of the .NET Framework. その結果、2 つの数値の比較は、数値の内部表現の有効桁数が変わる可能性がある .NET Framework のバージョン間変更可能性があります。Consequently, a comparison of two particular numbers might change between versions of the .NET Framework because the precision of the numbers' internal representation might change.

こちらもご覧ください

適用対象