StringBuilder.CopyTo Method in C#

This method is used to copy the characters from a specified segment of this instance to a specified segment of a destination Char array.

Syntax:

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

Parameters:

• sourceIndex: It is the starting position in this instance where characters will be copied from. The index is zero-based.
• destination: It is the array where characters will be copied.
• destinationIndex: It is the starting position in destination where characters will be copied. The index is zero-based.
• count: It is the number of characters to be copied.

Exceptions:

• ArgumentNullException: If the destination is null.
• ArgumentOutOfRangeException: If the sourceIndex, destinationIndex, or count, is less than zero or the sourceIndex is greater than the length of this instance.
• ArgumentException: If the sourceIndex + count is greater than the length of this instance or the destinationIndex + count is greater than the length of destination.

Example 1:

// C# program to illustrate the
// CopyTo () StringBuilder Method
using System;
using System.Text;

class Geeks {

    // Main Method
    public static void Main()
    {
        // create a StringBuilder object
        // with a String pass as parameter
        StringBuilder str
            = new StringBuilder("GeeksForGeeks");

        char[] dest = new char[15];

        // str index 5 to 5+3 has to
        // copy into Copystring
        // 3 is no. of character
        // 0 is start index of Copystring
        str.CopyTo(5, dest, 0, 3);

        // Displaying String
        Console.Write("The Copied String in "+
                        "dest Variable is: ");
        Console.WriteLine(dest);
    }
}

Output:

The Copied String in dest Variable is: For

Example 2:

// C# program to illustrate the
// CopyTo() StringBuilder Method
using System;
using System.Text;

class Geeks {

    // Main Method
    public static void Main()
    {
        // create a StringBuilder object
        // with a String pass as parameter
        StringBuilder str2
            = new StringBuilder("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
        str2.CopyTo(8, dest, 6, 5);

        // Displaying the result
        Console.Write("String Copied in dest is: ");
        Console.WriteLine(dest);
    }
}

Output:

String Copied in dest is: Hello Geeks

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.copyto?view=netframework-4.7.2