domains
    file = xinput
predicates
    start
    reading(integer)
    searching(integer,integer)
goal
    clearwindow,
    start.
clauses
    start:-
        openread(xinput,"data.txt"),
        readdevice(xinput),
        reading(1).

    reading(LineNo):-
        not(eof(xinput)),
        readln(Line),
        write(LineNo," ",Line),nl,
        LL = LineNo + 1,
        reading(LL).

    reading(_):-
        write("\nEnter Line No = "),
        readdevice(keyboard),
        readint(LineNo),
        filepos(xinput,0,0),
        readdevice(xinput),
        searching(LineNo,1).
        
    searching(LineNo,Num):-
        not(eof(xinput)),
        LineNo <> Num,
        readln(Line),
        NN = Num + 1,
        searching(LineNo,NN).
        
    searching(LineNo,Num):-
        not(eof(xinput)),
        readln(Line),
        closefile(xinput),
        openwrite(xinput,"Outputq6.txt"),
        writedevice(xinput),
        write(Line),nl,
        closefile(xinput),
        write("See file outputq6.txt").
        
    searching(LineNo,Num):-
        write("Enter line no. is outof file"),nl.