SIMSCRIPT II.5 Programming Language

SIMSCRIPT II.5 Programming Language
able, the first character of the input field will be read. In some earlier implementations, and where
an alpha variable may represent more than one character, a number of characters up to the maximum
representation size will be read. The column position pointer is advanced by the specified
field width.
When used in output statements, the A format will normally print the single character represented
by the alpha variable in the first column of the output field, padding any further positions with
blank spaces. When more than one character alpha representation is supported, a number of characters,
up to either the maximum representation, or the field width, may be printed.
3.4.2.6 C (Computer Representation) Descriptor
Few computers use decimal notation internally. Most use binary coding schemes that represent decimal
numbers as sequences of zeros and ones. Generally, a group of binary bits constituting a character
in a number system other than binary or decimal is used as an input/output character. Because
strings of such numbers are short, they are easy to interpret. Commonly used representations are
octal and hexadecimal, for groups of 3 and 4 binary bits, respectively.
The format n C e interprets characters read or written in the unit of the computer on which a particular
SIMSCRIPT II.5 system is implemented. The field width, e, specifies the number of character
positions occupied. Each position corresponds to a single octal or hexadecimal symbol, depending
on the particular machine implementation.
3.4.3 Format Lists
Format lists are composed of sequences of format descriptors separated by commas. During the
execution of read and write statements, format lists are scanned from left to right and individual
format descriptors are used as needed to match the variables named in the variable list. With few
exceptions, variables being read or expressions being written must agree in mode with their format
descriptors. The exceptions are integer and alpha modes that can be used interchangeably.
When they are interchanged, the mode of the format descriptor governs. When a format descriptor
is preceded by a repetition character n, n consecutive read and write statements that use formatted
data follow. Some examples of format lists are given below.
1. read X, ANSWER and Y as I 3, I 2, I 2
If one assumes they have data in an input data file, and the above statement — the first in
a program — starts reading at column 1 of the first input record, the value appearing in columns
1-3 is assigned to X, that in columns 4-5 is assigned to ANSWER, and the value in columns
6-7 is assigned to Y. The data might appear as:
column 0 1 ...
number 12345678901234
160 3 8
110