How Not to Program in C++ -- Updates

Program #13, Lines #25 & #27
'endl' is in std namespace, so both lines should read ...<< std::endl;

Program #19, Line #19
"default" should be "defualt" (should be misspelled)

Program #43, line #35
should be "class der: public base"

Program #44, line #32
should be "while (array[i] != -1)"

Program #46, line #56
should be "cur_cmd->cmd != NULL)"

Answer #57, first code
"20" should be "21"

Answer 70, line #56
should be "cur_cmd->cmd != NULL)"