c# - How to reverse a string

Reverse a String

The String represents text as a sequence of UTF-16 code units. The String is a sequential collection of characters that is used to represent text. The String is a sequential collection of System.Char objects.

The following .net c# tutorial code demonstrates how we can reverse a String object. So, in this .net c# tutorial code we will reverse String characters such as if a String instance contains the text ‘Yellow’ then we will reverse it as ‘wolleY’. It means we will rearrange the character’s position of a String instance from last to first and so on.

To reverse a String object, at first we will convert the String instance into a Char array. Then we reverse the elements of the Char array using the .net Array built-in method. Finally, we will create a new instance of the String object from the reversed Char Array object.

The String ToCharArray() method copies the characters in this instance to a Unicode character Array. The String ToCharArray() method returns a Unicode character Array whose elements are the individual characters of this instance. If this instance is an empty string then the returned Array is empty and has a zero length. So using this String ToCharArray() method we convert the String instance to a Char Array object.

The Array Reverse() method reverses the order of the elements in a one-dimensional Array or in a portion of the Array. The Array Reverse(Array) method overload reverses the sequence of the elements in the entire one-dimensional Array. So, using this Array Reverse() method we can reverse the order of elements in an Array.

The String String(Char[]) constructor initializes a new instance of the String class to the Unicode characters indicated in the specified character Array. So we can create an instance of a String object from the reversed Char Array. Finally, in this way, we reversed a String instance.

string-reverse.aspx


<%@ Page Language="C#" AutoEventWireup="true"%>

<!DOCTYPE html>  
<script runat="server"> 
    protected void Button1_Click(object sender, System.EventArgs e)  
    {
        //this section create a string variable.
        string characters = "ABCDEF";

        Label1.Text = "string of characters..................<br />";
        Label1.Text += characters + "<br /><br />";

        //this line create a char array from string.
        char[] chars = characters.ToCharArray();
        
        //this line reverse elements of char array.
        Array.Reverse(chars);
        
        //this line convert char array to string.
        string reversedString = new string(chars);
        
        Label1.Text += "<br />reversed string........<br />";
        Label1.Text += reversedString;
    }  
</script>  
  
<html xmlns="http://www.w3.org/1999/xhtml">  
<head id="Head1" runat="server">  
    <title>c# example - string reverse</title>  
</head>  
<body>  
    <form id="form1" runat="server">  
    <div>  
        <h2 style="color:MidnightBlue; font-style:italic;">  
            c# example - string reverse
        </h2>  
        <hr width="550" align="left" color="Gainsboro" />  
        <asp:Label   
            ID="Label1"   
            runat="server"  
            Font-Size="Large"
            >  
        </asp:Label>  
        <br /><br />
        <asp:Button   
            ID="Button1"   
            runat="server"   
            Text="string reverse"  
            OnClick="Button1_Click"
            Height="40"  
            Font-Bold="true"  
            />  
    </div>  
    </form>  
</body>  
</html>

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