create string builder in a new class using c#

As single characters for anything coding related are not advisable, it makes searching through code a bit of a mission (e.g. if your code contains a lot 'VeranaJam' but you want to find the 'v' for the class. I've therefore named the class vv.

    class vv
    {
        StringBuilder _sb;

        public vv()
        {
            _sb = new StringBuilder();
        }

        public vv(StringBuilder sb)
        {
            _sb = sb;
        }

        public StringBuilder replace(string strWhat, string strByWhat)
        {
            _sb.Replace(strWhat, strByWhat);
            return _sb;
        }

        public StringBuilder append(string strValue)
        {
            _sb = _sb.Append(strValue);
            return _sb;
        }
    }

This class contains two constructors; public vv() will simply create a new StringBuilder _sb while public vv(StringBuilder sb) will take an argument and assign that to _sb.

Next there are two methods that you can use; one to replace content and one to append content.

A console application example that uses both

        static void Main(string[] args)
        {
            vv vbuilder1 = new vv();
            vv vbuilder2 = new vv(new StringBuilder("hi, how are you"));

            vbuilder1.append("here we go");

            Console.WriteLine(vbuilder1.replace("hi", "hello VerenaJam").ToString());
            Console.WriteLine(vbuilder2.replace("hi", "hello VerenaJam").ToString());

            Console.ReadLine();
        }

This creates two independent instances of the class vv. vbuilder 1 will contain an empty StringBuilder object and vbuilder2 will contain a StringBuilder object with some content.

Next we append something to the StringBuilder object in vbuilder1 using the append method.

The two WriteLines call the replace methods and display the result.

The ReadLine is just there to wait for user input before the program ends.

I hope this helps