C# String CopyTo() Method

In C#, the CopyTo() is a method of String Class. It is used to copy a specified number of characters from a specified position in the string and it copies the characters of this string into an array of Unicode characters.

Example 1: Using the CopyTo() method to copy characters from a string to a character array.

// C# program to illustrate the // String.CopyTo() Method // Method using System; class Geeks { public static void Main() { // Creating a string string s = "GeeksForGeeks"; // Destination char array char[] dest = new char[3]; //Copying 3 characters from the 5th index  //of the string to the destination char array. s.CopyTo(5, dest, 0, 3);   // Displaying the copied string Console.WriteLine($"The Copied String is: {new string(dest)}"); } } 

The Copied String is: For 

Syntax of String CopyTo() Method

public void CopyTo(int sourceIndex, char[] destination, int destinationIndex, int count)

Parameters:

• sourceIndex: Index of String to be copied. Its type is System.Int32 .
• destination: It is the array of Unicode characters to which characters will be copied. Its type is System.Char[].
• destinationIndex: It is the the starting index of the array from where the copy operation begins. Its type is System.Int32.
• count: It is the number of characters which will copy to the destination. Its type is System.Int32.

Exceptions:

• ArgumentNullException: If the destination array is null then it will throw this Exception.
• ArgumentOutOfRangeException: There are different cases when an exception occurs
  • If sourceIndex, destinationIndex, or count is negative.
  • If sourceIndex does not identify a position in the current instance.
  • If destinationIndex does not identify a valid index in the destination array.
  • If the count is greater than the length of the substring from startIndex to the end of this instance
  • If the count is greater than the length of the subarray from destinationIndex to the end of the destination array.

Example 2: Using the CopyTo() method to modify an existing character array.

// C# program to illustrate the  // ToCopy() string method  using System;  class Geeks  {  public static void Main()  {  string s = "GeeksForGeeks";   char[] dest = {'H', 'e', 'l', 'l', 'o', ' ',   'W', 'o', 'r', 'l', 'd' };  // str index 8 to 8 + 5 has  // to copy into Copystring  // 5 is no of character  // 6 is start index of Copystring  s.CopyTo(8, dest, 6, 5);   // Displaying the result  Console.Write("String Copied in dest is: ");  Console.WriteLine(dest);  }  }  

String Copied in dest is: Hello Geeks