Int32 Structure

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.

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  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.

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  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 Option Strict 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.

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  long lNumber = 163245617;
  try {
     int number1 = (int) lNumber;
     Console.WriteLine(number1);
  }
  catch (OverflowException) {
     Console.WriteLine("{0} is out of range of an Int32.", lNumber);
  }
  
  double dbl2 = 35901.997;
  try {
     int number2 = (int) dbl2;
     Console.WriteLine(number2);
  }   
  catch (OverflowException) {
     Console.WriteLine("{0} is out of range of an Int32.", dbl2);
  }
  
  // The example displays the following output:
  //       163245617
  //       35902
  
  
  

• 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.

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  decimal[] values= { Decimal.MinValue, -1034.23m, -12m, 0m, 147m,
                      199.55m, 9214.16m, Decimal.MaxValue };
  int result;
  
  foreach (decimal value in values)
  {
     try {
        result = Convert.ToInt32(value);
        Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.",
                          value.GetType().Name, value,
                          result.GetType().Name, result);
     }
     catch (OverflowException) {
        Console.WriteLine("{0} is outside the range of the Int32 type.",
                          value);
     }   
  }                                  
  // The example displays the following output:
  //    -79228162514264337593543950335 is outside the range of the Int32 type.
  //    Converted the Decimal value '-1034.23' to the Int32 value -1034.
  //    Converted the Decimal value '-12' to the Int32 value -12.
  //    Converted the Decimal value '0' to the Int32 value 0.
  //    Converted the Decimal value '147' to the Int32 value 147.
  //    Converted the Decimal value '199.55' to the Int32 value 200.
  //    Converted the Decimal value '9214.16' to the Int32 value 9214.
  //    79228162514264337593543950335 is outside the range of the Int32 type.
  
  
  

• 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.

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  string string1 = "244681";
  try {
     int number1 = Int32.Parse(string1);
     Console.WriteLine(number1);
  }
  catch (OverflowException) {
     Console.WriteLine("'{0}' is out of range of a 32-bit integer.", string1);
  }
  catch (FormatException) {
     Console.WriteLine("The format of '{0}' is invalid.", string1);
  }
  
  string string2 = "F9A3C";
  try {
     int number2 = Int32.Parse(string2,
                              System.Globalization.NumberStyles.HexNumber);
     Console.WriteLine(number2);
  }
  catch (OverflowException) {
     Console.WriteLine("'{0}' is out of range of a 32-bit integer.", string2);
  }
  catch (FormatException) {
     Console.WriteLine("The format of '{0}' is invalid.", string2);
  }
  // The example displays the following output:
  //       244681
  //       1022524
  
  
  

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.

The Int32 type provides full support for standard and custom numeric format strings. (For more information, see Formatting Overview, 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.

int[] numbers = { -1403, 0, 169, 1483104 };
foreach (int number in numbers) {
   // Display value using default formatting.
   Console.Write("{0,-8}  -->   ", number.ToString());
   // Display value with 3 digits and leading zeros.
   Console.Write("{0,11:D3}", number);
   // Display value with 1 decimal digit.
   Console.Write("{0,13:N1}", number);
   // Display value as hexadecimal.
   Console.Write("{0,12:X2}", number);
   // Display value with eight hexadecimal digits.
   Console.WriteLine("{0,14:X8}", number);
}   
// 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.

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

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.