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Numeric precision and representation issues are well-known topics in computer science. Non computer scientists sometimes are not aware of the problems that occur with these issues. This paper provides a brief introduction to problems based on numeric precision and the presentation of numbers on computerized systems. Numbers are stored as binary numbers in computerized systems. However, not all floating-point numbers can be represented properly in the binary system. When calculating with numbers that cannot be stored exactly, the result may not be as expected. In our case, 4.8 and 4.6 can not be stored exactly and therefore, the result of 4.8 minus 4.6 will not be exactly 0.2. The conversion of floating-point numbers to a storable IEEE-754 binary number is illustrated. Finally, some SAS functions and options are introduced that may help to deal with the issue. [ABSTRACT FROM AUTHOR]

Sometimes the simplest SAS® task can become unnecessarily complex. Often the complexity of SAS®, itself, is the cause. Crucial details are easily hidden among the thousands of pages of SAS® documentation, technical notes, release updates, etc. The authors demonstrate a collection of SAS® features and techniques that are not well known, somewhat counterintuitive or undocumented, but all are surprisingly useful once learned and mastered. Mysterious SAS® behavior that might have inspired ‘work-arounds’ should now become transparent. Topics include environment settings; system options; and operators, functions and statements from SAS Language®, Macro Language®, SCL® and SAS/Graph®. The authors intend, through this selective review of uncommon techniques, to inspire a general interest in leveraging the power and maximizing the efficiency of programming tools. [ABSTRACT FROM AUTHOR]

A macro that can take more or fewer arguments when it is called than formally declared is often referred to as a variable argument (or varargs) macro. The SAS® macro facility provides a basic mechanism for constructing a varargs macro. When properly developed, a single varargs macro can be used to solve arrays of problems of the same form all together in an orderly and uniform way, which can be especially valuable to the development of standard macros used in pharmaceutical programming. This article first describes the way to define a typical varargs macro using the option PBUFF in the %Macro statement, as well as two simulated methods. It then explores common calling conventions for varargs macros and various approaches to implementing varargs macros based on how individual arguments can be retrieved from varargs lists passed at runtime. In addition, the advantages and disadvantages of using varargs macros are briefly discussed, and the techniques are illustrated with various examples. [ABSTRACT FROM AUTHOR]