Articolo
11/18/2011

Int32 Structure

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Represents a 32-bit signed integer.

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

Syntax

'Declaration
<ComVisibleAttribute(True)> _
Public Structure Int32 _
    Implements IComparable, IFormattable, IConvertible, IComparable(Of Integer),  _
    IEquatable(Of Integer)

[ComVisibleAttribute(true)]
public struct Int32 : IComparable, IFormattable, 
    IConvertible, IComparable<int>, IEquatable<int>

The Int32 type exposes the following members.

Methods

	Name	Description
	CompareTo(Int32)	Compares this instance to a specified 32-bit signed integer and returns an integer that indicates whether the value of this instance is greater than, less than, or equal to the value of the specified 32-bit signed integer.
	CompareTo(Object)	Compares this instance to a specified object and returns an integer that indicates whether the value of this instance is greater than, less than, or equal to the value of the specified object.
	Equals(Int32)	Returns a value indicating whether this instance is equal to a specified Int32 value.
	Equals(Object)	Returns a value indicating whether this instance is equal to a specified object. (Overrides ValueType.Equals(Object).)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
	GetHashCode	Returns the hash code for this instance. (Overrides ValueType.GetHashCode().)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	GetTypeCode	Returns the TypeCode for value type Int32.
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	Parse(String)	Converts the string representation of a number to its 32-bit signed integer equivalent.
	Parse(String, NumberStyles)	Converts the string representation of a number in a specified style to its 32-bit signed integer equivalent.
	Parse(String, IFormatProvider)	Converts the string representation of a number in a specified culture-specific format to its 32-bit signed integer equivalent.
	Parse(String, NumberStyles, IFormatProvider)	Converts the string representation of a number in a specified style and culture-specific format to its 32-bit signed integer equivalent.
	ToString()	Converts the numeric value of this instance to its equivalent string representation. (Overrides ValueType.ToString().)
	ToString(IFormatProvider)	Converts the numeric value of this instance to its equivalent string representation using the specified culture-specific format information.
	ToString(String)	Converts the numeric value of this instance to its equivalent string representation, using the specified format.
	ToString(String, IFormatProvider)	Converts the numeric value of this instance to its equivalent string representation using the specified format and culture-specific format information.
	TryParse(String, Int32%)	Converts the string representation of a number to its 32-bit signed integer equivalent. A return value indicates whether the conversion succeeded.
	TryParse(String, NumberStyles, IFormatProvider, Int32%)	Converts the string representation of a number in a specified style and culture-specific format to its 32-bit signed integer equivalent. A return value indicates whether the conversion succeeded.

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Fields

	Name	Description
	MaxValue	Represents the largest possible value of an Int32. This field is constant.
	MinValue	Represents the smallest possible value of Int32. This field is constant.

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Explicit Interface Implementations

	Name	Description
	IConvertible.ToBoolean	Infrastructure. For a description of this member, see IConvertible.ToBoolean.
	IConvertible.ToByte	Infrastructure. For a description of this member, see IConvertible.ToByte.
	IConvertible.ToChar	Infrastructure. For a description of this member, see IConvertible.ToChar.
	IConvertible.ToDateTime	Infrastructure. This conversion is not supported. Attempting to use this method throws an InvalidCastException.
	IConvertible.ToDecimal	Infrastructure. For a description of this member, see IConvertible.ToDecimal.
	IConvertible.ToDouble	Infrastructure. For a description of this member, see IConvertible.ToDouble.
	IConvertible.ToInt16	Infrastructure. For a description of this member, see IConvertible.ToInt16.
	IConvertible.ToInt32	Infrastructure. For a description of this member, see IConvertible.ToInt32.
	IConvertible.ToInt64	Infrastructure. For a description of this member, see IConvertible.ToInt64.
	IConvertible.ToSByte	Infrastructure. For a description of this member, see IConvertible.ToSByte.
	IConvertible.ToSingle	Infrastructure. For a description of this member, see IConvertible.ToSingle.
	IConvertible.ToType	Infrastructure. For a description of this member, see IConvertible.ToType.
	IConvertible.ToUInt16	Infrastructure. For a description of this member, see IConvertible.ToUInt16.
	IConvertible.ToUInt32	Infrastructure. For a description of this member, see IConvertible.ToUInt32.
	IConvertible.ToUInt64	Infrastructure. For a description of this member, see IConvertible.ToUInt64.

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Remarks

Int32 is an immutable value type that represents signed integers with values that range from negative 2,147,483,648 (which is represented by the Int32.MinValue constant) through positive 2,147,483,647 (which is represented by the Int32.MaxValue constant. The .NET Framework also includes an unsigned 32-bit integer value type, UInt32, which represents values that range from 0 to 4,294,967,295.

Instantiating an Int32 Value

You can instantiate an Int32 value in several ways:

You can declare an Int32 variable and assign it a literal integer value that is within the range of the Int32 data type. The following example declares two Int32 variables and assigns them values in this way.
```
Dim number1 As Integer = 64301
Dim number2 As Integer = 25548612
```
```
int number1 = 64301;
int number2 = 25548612;
```

You can assign the value of an integer type whose range is a subset of the Int32 type. This is a widening conversion that does not require a cast operator in C# or a conversion method in Visual Basic.

Dim value1 As SByte = 124
Dim value2 As Int16 = 1618

Dim number1 As Integer = value1
Dim number2 As Integer = value2

sbyte value1 = 124;
short value2 = 1618;

int number1 = value1;
int number2 = value2;

You can assign the value of a numeric type whose range exceeds that of the Int32 type. This is a narrowing conversion, so it requires a cast operator in C# and a conversion method in Visual Basic if OptionStrict is on. If the numeric value is a Single, Double, or Decimal value that includes a fractional component, the handling of its fractional part depends on the compiler performing the conversion. The following example performs narrowing conversions to assign several numeric values to Int32 variables.

Dim lNumber As Long = 163245617
Try
   Dim number1 As Integer = CInt(lNumber)
   outputBlock.Text &= number1 & vbCrLf
Catch e As OverflowException
   outputBlock.Text += String.Format("{0} is out of range of an Int32.", lNumber) & vbCrLf
End Try

Dim dbl2 As Double = 35901.997
Try
   Dim number2 As Integer = CInt(dbl2)
   outputBlock.Text &= number2 & vbCrLf
Catch e As OverflowException
   outputBlock.Text += String.Format("{0} is out of range of an Int32.", dbl2) & vbCrLf
End Try

Dim bigNumber As BigInteger = 132451
Try
   Dim number3 As Integer = CInt(bigNumber)
   outputBlock.Text &= number3 & vbCrLf
Catch e As OverflowException
   outputBlock.Text += String.Format("{0} is out of range of an Int32.", bigNumber) & vbCrLf
End Try
' The example displays the following output:
'       163245617
'       35902
'       132451

long lNumber = 163245617;
try
{
   int number1 = (int)lNumber;
   outputBlock.Text += number1 + "\n";
}
catch (OverflowException)
{
   outputBlock.Text += String.Format("{0} is out of range of an Int32.", lNumber) + "\n";
}

double dbl2 = 35901.997;
try
{
   int number2 = (int)dbl2;
   outputBlock.Text += number2 + "\n";
}
catch (OverflowException)
{
   outputBlock.Text += String.Format("{0} is out of range of an Int32.", dbl2) + "\n";
}

BigInteger bigNumber = 132451;
try
{
   int number3 = (int)bigNumber;
   outputBlock.Text += number3 + "\n";
}
catch (OverflowException)
{
   outputBlock.Text += String.Format("{0} is out of range of an Int32.", bigNumber) + "\n";
}
// The example displays the following output:
//       163245617
//       35902
//       132451

You can call a method of the Convert class to convert any supported type to an Int32 value. This is possible because Int32 supports the IConvertible interface. The following example illustrates the conversion of an array of Decimal values to Int32 values.

You can call the Parse or TryParse method to convert the string representation of an Int32 value to an Int32. The string can contain either decimal or hexadecimal digits. The following example illustrates the parse operation by using both a decimal and a hexadecimal string.

Dim string1 As String = "244681"
Try
   Dim number1 As Integer = Int32.Parse(string1)
   outputBlock.Text &= number1 & vbCrLf
Catch e As OverflowException
   outputBlock.Text += String.Format("'{0}' is out of range of a 32-bit integer.", string1) & vbCrLf
Catch e As FormatException
   outputBlock.Text += String.Format("The format of '{0}' is invalid.", string1) & vbCrLf
End Try

Dim string2 As String = "F9A3C"
Try
   Dim number2 As Integer = Int32.Parse(string2,
                            System.Globalization.NumberStyles.HexNumber)
   outputBlock.Text &= number2 & vbCrLf
Catch e As OverflowException
   outputBlock.Text += String.Format("'{0}' is out of range of a 32-bit integer.", string2) & vbCrLf
Catch e As FormatException
   outputBlock.Text += String.Format("The format of '{0}' is invalid.", string2) & vbCrLf
End Try
' The example displays the following output:
'       244681
'       1022524

string string1 = "244681";
try
{
   int number1 = Int32.Parse(string1);
   outputBlock.Text += number1 + "\n";
}
catch (OverflowException)
{
   outputBlock.Text += String.Format("'{0}' is out of range of a 32-bit integer.", string1) + "\n";
}
catch (FormatException)
{
   outputBlock.Text += String.Format("The format of '{0}' is invalid.", string1) + "\n";
}

string string2 = "F9A3C";
try
{
   int number2 = Int32.Parse(string2,
                            System.Globalization.NumberStyles.HexNumber);
   outputBlock.Text += number2 + "\n";
}
catch (OverflowException)
{
   outputBlock.Text += String.Format("'{0}' is out of range of a 32-bit integer.", string2) + "\n";
}
catch (FormatException)
{
   outputBlock.Text += String.Format("The format of '{0}' is invalid.", string2) + "\n";
}
// The example displays the following output:
//       244681
//       1022524

Performing Operations on Int32 Values

The Int32 type supports standard mathematical operations such as addition, subtraction, division, multiplication, subtraction, negation, and unary negation. Like the other integral types, the Int32 type also supports the bitwise AND, OR, XOR, left shift, and right shift operators.

You can use the standard numeric operators to compare two Int32 values, or you can call the CompareTo or Equals method.

Representing an Int32 as a String

The Int32 type provides full support for standard and custom numeric format strings. (For more information, see Formatting Types, Standard Numeric Format Strings, and Custom Numeric Format Strings.)

To format an Int32 value as an integral string with no leading zeros, you can call the parameterless ToString() method. By using the "D" format specifier, you can also include a specified number of leading zeros in the string representation. By using the "N" format specifier, you can include group separators and specify the number of decimal digits to appear in the string representation of the number. By using the "X" format specifier, you can represent an Int32 value as a hexadecimal string. The following example formats the elements in an array of Int32 values in these four ways.

Dim numbers() As Integer = {-1403, 0, 169, 1483104}
For Each number As Integer In numbers
   ' Display value using default formatting.
   outputBlock.Text += String.Format("{0,-8}  -->   ", number.ToString())
   ' Display value with 3 digits and leading zeros.
   outputBlock.Text += String.Format("{0,11:D3}", number)
   ' Display value with 1 decimal digit.
   outputBlock.Text += String.Format("{0,13:N1}", number)
   ' Display value as hexadecimal.
   outputBlock.Text += String.Format("{0,12:X2}", number)
   ' Display value with eight hexadecimal digits.
   outputBlock.Text += String.Format("{0,14:X8}", number) & vbCrLf
Next
' The example displays the following output:
'    -1403     -->         -1403     -1,403.0    FFFFFA85      FFFFFA85
'    0         -->           000          0.0          00      00000000
'    169       -->           169        169.0          A9      000000A9
'    1483104   -->       1483104  1,483,104.0      16A160      0016A160

int[] numbers = { -1403, 0, 169, 1483104 };
foreach (int number in numbers)
{
   // Display value using default formatting.
   outputBlock.Text += String.Format("{0,-8}  -->   ", number.ToString());
   // Display value with 3 digits and leading zeros.
   outputBlock.Text += String.Format("{0,11:D3}", number);
   // Display value with 1 decimal digit.
   outputBlock.Text += String.Format("{0,13:N1}", number);
   // Display value as hexadecimal.
   outputBlock.Text += String.Format("{0,12:X2}", number);
   // Display value with eight hexadecimal digits.
   outputBlock.Text += String.Format("{0,14:X8}", number) + "\n";
}
// The example displays the following output:
//    -1403     -->         -1403     -1,403.0    FFFFFA85      FFFFFA85
//    0         -->           000          0.0          00      00000000
//    169       -->           169        169.0          A9      000000A9
//    1483104   -->       1483104  1,483,104.0      16A160      0016A160

You can also format an Int32 value as a binary, octal, decimal, or hexadecimal string by calling the ToString(Int32, Int32) method and supplying the base as the method's second parameter. The following example calls this method to display the binary, octal, and hexadecimal representations of an array of integer values.

Dim numbers() As Integer = {-146, 11043, 2781913}
outputBlock.Text += String.Format("{0,8}   {1,32}   {2,11}   {3,10}", _
                  "Value", "Binary", "Octal", "Hex") & vbCrLf
For Each number As Integer In numbers
   outputBlock.Text += String.Format("{0,8}   {1,32}   {2,11}   {3,10}", _
                     number, Convert.ToString(number, 2), _
                     Convert.ToString(number, 8), _
                     Convert.ToString(number, 16)) & vbCrLf
Next
' The example displays the following output:
'       Value                             Binary         Octal          Hex
'        -146   11111111111111111111111101101110   37777777556     ffffff6e
'       11043                     10101100100011         25443         2b23
'     2781913             1010100111001011011001      12471331       2a72d9

int[] numbers = { -146, 11043, 2781913 };
outputBlock.Text += String.Format("{0,8}   {1,32}   {2,11}   {3,10}",
                  "Value", "Binary", "Octal", "Hex") + "\n";
foreach (int number in numbers)
{
   outputBlock.Text += String.Format("{0,8}   {1,32}   {2,11}   {3,10}",
                     number, Convert.ToString(number, 2),
                     Convert.ToString(number, 8),
                     Convert.ToString(number, 16)) + "\n";
}
// The example displays the following output:
//       Value                             Binary         Octal          Hex
//        -146   11111111111111111111111101101110   37777777556     ffffff6e
//       11043                     10101100100011         25443         2b23
//     2781913             1010100111001011011001      12471331       2a72d9

Working with Non-Decimal 32-Bit Integer Values

In addition to working with individual integers as decimal values, you may want to perform bitwise operations with integer values, or work with the binary or hexadecimal representations of integer values. Int32 values are represented in 31 bits, with the thirty-second bit used as a sign bit. Positive values are represented by using sign-and-magnitude representation. Negative values are in two's complement representation. This is important to keep in mind when you perform bitwise operations on Int32 values or when you work with individual bits. In order to perform a numeric, Boolean, or comparison operation on any two non-decimal values, both values must use the same representation.

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Thread Safety

All members of this type are thread safe. Members that appear to modify instance state actually return a new instance initialized with the new value. As with any other type, reading and writing to a shared variable that contains an instance of this type must be protected by a lock to guarantee thread safety.

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