Reading a File

Here is a QBasic program that reads the data file you just created. The program reads in each integer, then prints it to the screen. Start QBasic in the same subdirectory that holds the data file. Enter and run the program in the usual way.

' Read in and echo the first three
' integers in DATA.DAT
'
CLS                              ' Clear the output screen
OPEN "DATA.DAT" FOR INPUT AS #1  ' Open the file for INPUT
INPUT #1, NUM                    ' Read in the first number
PRINT NUM                        ' Print out the first number
INPUT #1, NUM                    ' Read in the second number
PRINT NUM                        ' Print out the second number
INPUT #1, NUM                    ' Read in the third number
PRINT NUM                        ' Print out the third number
END

First the program clears away whatever characters my be in the DOS window. Then it opens the disk file DATA.DAT. Opening a file for INPUT means finding it on the disk and preparing it for reading. After the file has been opened, it corresponds to file number #1. The statements that read the file are nearly the same as the INPUT statements that read data from the keyboard.