C# | Char.IsControl(String, Int32) Method
Last Updated :
11 Jul, 2025
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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)
// Method
using 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 IsControl() 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}' doesn't contain control "+
"character at index {1}", s, i);
}
}
// 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 IsControl() 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}' doesn't contain control "+ "character at index {1}", s, i); }}Example 2: For ArgumentNullException
// C# program to demonstrate the
// Char.IsControl(String, Int32)
// Method
using 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 IsControl() 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}' doesn't contain "+
"control character at index {1}", s, i);
}
}
// 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 IsControl() 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}' doesn't contain "+ "control character at index {1}", s, i); }}Output:
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)
// Method
using 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 IsControl() 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}' doesn't contain control"+
" character at index {1}", s, i);
}
}
// 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 IsControl() 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}' doesn't contain control"+ " character at index {1}", s, i); }}Output:
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
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