Create String

  String MyString;

Combining strings

  MyString = String("abc" + "def" + SomeOtherString);

Replace

MyString.replace("\n", "");

String to char

  char *p_source_string;
  p_source_string = (char*)source_string.c_str();
  if (*p_source_string++ == 'a')
  {
    
  }

Is String Null?

    if (MyString != NULL)
    {
    }