SIMSCRIPT II.5 Programming Language

Programming Language Concepts
Table 2-3. System-Defined Constants
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Standard
Name Symbol Value Units Mode
pi.c p 3.141159265 -- Real *
Exp.c e 2.718281828 -- Real *
inf.c ∞ Largest value -- Integer
computer can store
Rinf.c ∞ Largest value -- Real *
computer can store
Radian.c - 57.29577 Degrees/radian Real *
* On systems that support additional precision, these constants are of double mode.
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2.5 Subscripted Variables
Variables as described above may represent single, numeric data items in SIMSCRIPT II.5. A feature
of many programming languages is the facility to represent and manipulate data in a way that
reflects the natural structure of the data. Data occurring in the form of lists or tables, for example,
have a regular structure. SIMSCRIPT II.5 provides a structure by which a number of similar data
items, the array elements, may be collectively referenced by a single name, while each individual
element may be referenced by subscripting the array name with an index value.
A simply ordered collection of data items, such as a list (figure 2-1), is represented by a one-dimensional
array. The elements of this array can be referenced by an identifying name, LIST, for example,
and an index number, called the array subscript, which can assume integer values from 1 up to
the total number of elements in the list. The array name is used to identify the collection of elements.
The subscript, enclosed in parentheses after the array name, is used to denote particular elements.
Thus, the name of the variable that is the first element in the array LIST is LIST(1), the
fifth element is called LIST(5), and the I th element is LIST(I). Figure 2-2 shows the list of figure
2-1 with the individual element names inserted.
Figure 2-1. A List Structure: One-dimensional Array
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