C# | Char.IsControl(String, Int32) Method - GeeksforGeeks

01 Feb, 2019
This method is used to indicates whether the character at the specified position in a specified string is categorized as a control character.
Syntax:
public static bool IsControl (string s, int index);
Parameters:
s: It is the String.
index: It is the character position in s.
Return Value: This method returns true if the character at position index in s is a control character otherwise it returns, false.
Exceptions:
ArgumentNullException: If the s is null.
ArgumentOutOfRangeException: If the index is less than zero or greater than the last position in s.
Note: Control characters are formatting and other non-printing characters, such as ACK, BEL, CR, FF, LF, and VT.
Below programs illustrate the use of Char.IsControl(String, Int32) Method:
Example 1:
// C# program to demonstrate the// Char.IsControl(String, Int32) // Methodusing System;  class GFG {      // Main Method    public static void Main()    {          try {              // calling check() Method            check("1234", 3);            check("Tsunami", 3);            check("psyc0lo", 4);            check("a" + Environment.NewLine + "b", 1);        }          catch (ArgumentNullException e) {              Console.Write("Exception Thrown: ");            Console.Write("{0}", e.GetType(), e.Message);        }          catch (ArgumentOutOfRangeException e) {              Console.Write("Exception Thrown: ");            Console.Write("{0}", e.GetType(), e.Message);        }    }      // Defining check() method    public static void check(string s, int i)    {          // checking condition        // using GetNumericValue() Method        bool val = Char.IsControl(s, i);          // checking        if (val)            Console.WriteLine("Control character \\U{0} "+                                 "found in position {1}.",                  Convert.ToInt32(s[i]).ToString("X4"), i);          else            Console.WriteLine("String '{0}' does't contain control "+                                      "character at index {1}", s, i);    }}
String '1234' does't contain control character at index 3
String 'Tsunami' does't contain control character at index 3
String 'psyc0lo' does't contain control character at index 4
Control character \U000A found in position 1.

Example 2: For ArgumentNullException
// C# program to demonstrate the// Char.IsControl(String, Int32) // Methodusing System;  class GFG {      // Main Method    public static void Main()    {        try {              // calling check() Method            check("1234", 3);            check("psyc0lo", 4);            check("a" + Environment.NewLine + "b", 1);            Console.WriteLine("");            Console.WriteLine("s is null");            check(null, 4);        }        catch (ArgumentNullException e) {              Console.Write("Exception Thrown: ");            Console.Write("{0}", e.GetType(), e.Message);        }        catch (ArgumentOutOfRangeException e) {              Console.Write("Exception Thrown: ");            Console.Write("{0}", e.GetType(), e.Message);        }    }      // Defining check() method    public static void check(string s, int i)    {        // checking condition        // using GetNumericValue() Method        bool val = Char.IsControl(s, i);          // checking        if (val)            Console.WriteLine("Control character \\U{0} found"+                                           " in position {1}.",                       Convert.ToInt32(s[i]).ToString("X4"), i);        else            Console.WriteLine("String '{0}' does't contain "+                     "control character at index {1}", s, i);    }}
String '1234' does't contain control character at index 3
String 'psyc0lo' does't contain control character at index 4
Control character \U000A found in position 1.

s is null
Exception Thrown: System.ArgumentNullException

Example 3: For ArgumentOutOfRangeException
// C# program to demonstrate the// Char.IsControl(String, Int32) // Methodusing System;  class GFG {      // Main Method    public static void Main()    {        try {              // calling check() Method            check("1234", 3);            check("psyc0lo", 4);            check("a" + Environment.NewLine + "b", 1);              Console.WriteLine("");            Console.WriteLine("index is less than zero");              check("null", -1);        }        catch (ArgumentNullException e) {              Console.Write("Exception Thrown: ");            Console.Write("{0}", e.GetType(), e.Message);        }        catch (ArgumentOutOfRangeException e) {              Console.Write("Exception Thrown: ");            Console.Write("{0}", e.GetType(), e.Message);        }    }      // Defining check() method    public static void check(string s, int i)    {        // checking condition        // using GetNumericValue() Method        bool val = Char.IsControl(s, i);          // checking        if (val)            Console.WriteLine("Control character \\U{0} found "+                                              "in position {1}.",                        Convert.ToInt32(s[i]).ToString("X4"), i);        else            Console.WriteLine("String '{0}' does't contain control"+                                   " character at index {1}", s, i);    }}
String '1234' does't contain control character at index 3
String 'psyc0lo' does't contain control character at index 4
Control character \U000A found in position 1.

index is less than zero
Exception Thrown: System.ArgumentOutOfRangeException

Reference:
https://docs.microsoft.com/en-us/dotnet/api/system.char.iscontrol?view=netframework-4.7.2#System_Char_IsControl_System_String_System_Int32_
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