SIMSCRIPT II.5 Programming Language

SIMSCRIPT II.5 Basic Concepts
ever the logical intent of a program is not immediately evident from its SIMSCRIPT II.5 instruction
sequences. The use of comments will be illustrated in many of the example programs below.
1.22 Some Sample SIMSCRIPT II.5 Level 1 Programs
The following programs illustrate the SIMSCRIPT II.5 concepts and statements presented in this
chapter. The programs are printed as they might appear before being submitted for compilation.
The flexibility of SIMSCRIPT II.5 makes many program statement formats possible. Those used
here are examples only.
1.22.1 Roots of a Quadratic Expression
The following example, demonstrating the use of nested if statements, calculates the roots of a
quadratic equation, which may be expressed in the general form:
AX 2 + BX + C = 0
First, the coefficients, A, B, and C, are read from input data. They are printed so that they may be
checked for any input errors. The coefficients are then tested for the trivial zero, constant, or linear
cases. Otherwise, the roots, alpha and beta, may be calculated from the familiar formulae:
alpha = -B + (B**2 - 4AC)**(1/2)
2A
beta = -B - (B**2 - 4AC)**(1/2)
2A
Before obtaining the square root, the sign of the sub-expression B 2 - 4AC is evaluated. If this value
is less than zero, the roots have complex values; otherwise, real values. Notice how the print
statement, as used in the example, can be used to print both the program title and the labeled variable
names.
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