changing datafile

[Michael]

hey people i got this problem with my datafile program

my program loads a datafile that display first names, last names, ages, genders and marks for a bunch of students.
I want the user to be able to change the datafile without actually going to the text file ...
i know how to erase all students.. just open and close the datafile but i want the user to be able to erase a certain name
how would i do that?

now the user is able to enter new students to the datafile but not erase/change info of current students

this is my proc for displaying the datafile

code:

%%%%%%%%%%%%% DISPLAY DATAFILE %%%%%%%%%%%5% proc writeArrays %display datafile     var count : int := 0     var avgage : real     var spacing : string := ".  "     Initial     storeValues     include "colours.t"         %include background and colour settings     colorback (40)     color (white)     locate (2, 3)     put "#" : 2, " First name" : 21, "Last name" : 17, "Gender   " : 17, "Age" : 15, "Mark" .. %heading     for ctr : 1 .. howMany         if fname (ctr) > "0" then %check if datafile has records             if gender (ctr) = "f" then %capitalize gender on output                 gender (ctr) := "F"             elsif gender (ctr) = "m" then                 gender (ctr) := "M"             end if             if ctr > 9 then                 spacing := ". "             else                 spacing := ".  "             end if             colorback (black)             locate (ctr + 3, 3) %locate content             put ctr, spacing, fname (ctr) : 20, lname (ctr) : 17, gender (ctr) : 17, age (ctr) : 3, mark (ctr) : 14, "%" ..                                 %display datafile             delay (50)             count += 1         else             colorback (black)             locate (4, 3)             put "Datafile has no student records" ..             locate (5, 3)             put "Please go back and add students to datafile" ..         end if     end for     locate (24, 60)     put "Total students: ", count ..     locate (24, 3)     include "wait1.t" %back to menu end writeArrays

and this is the erase student proc

code:

proc nameErase (var a : array 1 .. * of int, var num2 : int, howMany : int)     Initial     storeValues     var x, count, num : int := 5     count := 0     cls     include "colours.t"                 %include background and colour settings     colorback (40)     color (white)     locate (2, 3)     put "Enter student # to erase"     get num for ctr : 1.. howMany student.fname (num) := "0" end for     locate (24, 3)     include "wait1.t"         %back to menu end nameErase

but this doesnt work.. unless i display the datafile in that same proc but i want to physically delete it from the datafile
i know im missing something here.. like opening or closing datafile again but im not sure