Which of the following code snippets are legal for writing data to a text file?

Selectone or more:

ofstream streamObj$("$example$.$txt$",$ true$)$;

ifstream streamObj$("$example$.$txt$",$ ios:in$)$;

ifstream streamObj$("$example$.$txt$",$ ios::out$)$;

fstream streamObj$("$example$.$txt$",$ true$)$;

ofstream streamObj$($example$.$txt$",$ ios:app$)$;

fstream streamObj$("$example$.$txt$",$ los::app$)$;

ifstream streamObj$($example$.$txt$",$ false$)$;

ofstream streamObj$("$example$.$txt$",$ ios:out$)$;