static void StringContenation()
{
#region badcode
string str = string.Empty; // always assign string.Empty when declare string variable
for (int i = 0; i < 2000; i++)
{
str += str + i;
}
#endregion
#region goodcodepractice
StringBuilder strb = new StringBuilder();
for (int i = 0; i < 2000; i++)
{
strb.Append(i);
}
#endregion
}