Signed overpunch
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A signed overpunch is a code used to store the sign of a number by changing the last digit. It was used in old punched card systems and was carried over to COBOL, especially when using EBCDIC. Its purpose is to save a character that would otherwise be used by the sign digit.[1]
[edit] The codes
Code | Digit | Sign |
---|---|---|
} | 0 | − |
J | 1 | − |
K | 2 | − |
L | 3 | − |
M | 4 | − |
N | 5 | − |
O | 6 | − |
P | 7 | − |
Q | 8 | − |
R | 9 | − |
{ | 0 | + |
A | 1 | + |
B | 2 | + |
C | 3 | + |
D | 4 | + |
E | 5 | + |
F | 6 | + |
G | 7 | + |
H | 8 | + |
I | 9 | + |
[edit] Examples
10} is -100
45A is 451
Decimal points are usually implied not explicit in the text. Using numbers with two decimal digits:
1000} is -100.00