I need to import file from one application to another, unfortunately the file format layout are different with my database, sometime it contains more/less character in a field, sometimes it can be different character type. How do i write a program to convert this issues.
Any idea is greatly appreciated.

Your situation soulnds like you would be best to build a conversion program. Load your new empty file with an approriate size to hold all the records from the existing file then write a simple conversion program that reads from one file, transfers the data to the new record then writes the record out. Good Luck.

The incoming file can be thousands of different format, do you think writing an empty file for those thousands different format can be very time consuming, do you have a better way?
thanks you so much.