The first thing to note is that business data tend to be variable length. A list of
debits might include the strings 3.12, 1003.47, 67.18, etc.
Consider the problem of reading a list of signed integers. We specify that each
integer will have between 1 and 7 digits and be found in columns 1 – 8 of the punch card.
Here is a typical list.
123
-765
17765
-96