Question

how i can do this in c#

Explosive;a dynamic person

if i do split then ; is removed from text

how i can make them

Explosive;A dynamic person

Answer 1

string s = "Explosive;a dynamic person";
var separatorIndex = s.IndexOf(";");
if (separatorIndex != -1 && separatorIndex < s.Length + 1)
    s = s.Substring(0, separatorIndex + 1) + s.Substring(separatorIndex + 1, 1).ToUpper() + s.Substring(separatorIndex + 2);

Console.WriteLine(s);

gives “Explosive;A dynamic person”

I guess you would like something more general, but it is hard to figure out from the question how general you want it.