How does one create the process where a user can open (select) a file to read from? In C++ there are already classes to inherit from. Do I have to make a file open form from scratch in VB?

So far, the programs you have created have stored data in the computer’s memory in the form of variables. Memory is only a temporary storage while the computer is turned on and a program is running. A file is a collection of related data stored on a persistent medium such as a hard drive, a CD, or a diskette. (Persistent simply means lasting.) A file is different from a program and can be read from and written to by more than one program. Files are often used to provide data to a program. They are identified by the computer’s operating system with filenames assigned by the user.

There are three common data types:
• Sequential access files
• Direct access files
• Database files


Sequential file

• contains only plain text (i.e., text contains only ANSI ( American National Standards
Institute) text characters and the newline character, which is a carriage return-linefeed)
• can be prepared by NotePad or WordPad, but must be saved as text file
• data records must be input (read) one character at a time, in the same order that they were
placed on the file. (This is why it is called sequential.)
• each file ends with an EOF (end of file) marker
• Open, Input &Write
� Open “filename� For mode As #filenumber
 filename is the name of the file to be opened including its full path
 mode is either Input for reading the contents of the file or Output or Append for writing text to a file
 filenumber is a number, between 1 and 511, used to refer to the file
e.g., Open “a:\SumData.txt� For Input As #10
ï?± Input #n, list of variables (to input/read data from the file once it is opened)
Must be a one-to-one match (in terms of number and data type) between the list of variables and the data on the file
e.g., Input #10 houseNumber
Input #10 street
� Open “filename� for Output As #n
e.g., Open “a:\SumData.txt� for Output as #1
ï?± Write #n, list of variables (to output/write data on the file once it is opened)
• Close statement (use the statement when the program is terminated)
Close #n e.g., Close #10

Dim name As string, wage as single, hours as single
dim pay as currency

picPay.cls

open"staff.txt" for input as #1 'open data file
input #1, name, wage, hrs ' read in first employee's record
pay = wage * hrs 'calculate pay
picPay.print name, format(pay, "currency")
input #1, name, wage, hrs 'read in second employee's record
pay = wage * hrs 'calculate pay
picPay.Print name, format(pay, "currency")
Close #1