.NET Fiddle

CSharp · Console

/Program.cs

using System;
					
public class Program
{
	public static void Main()
	{
		string inputStr = "(abc)&&(rfd)&&(5)||(hh)&&(nn)||(iu)";
		string[] strWithoutAndOR = inputStr.Split(new string[] { "&&","||" }, StringSplitOptions.None);
		string[] strWithoutBrackets = inputStr.Split(new string[] { "&&","||","(",")" }, StringSplitOptions.RemoveEmptyEntries);
		Console.WriteLine("string Without And,OR           : {0}",String.Join(" ",strWithoutAndOR));
		Console.WriteLine("string Without And,OR, brackets : {0}",String.Join(" ",strWithoutBrackets));
	}
}