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Chapter 4 Program Design of Data StepZhang YuhuaInstitute of Biomedical Engineering Building 8, 3rd floor, east sideTel:mail: zhangyh@sdu.edu.cnMain TopicsLoop programming DO – END statementBranch programming IF – THEN/ELSE statementChapter 4Loop programmingLoop: In the one processing of DATA step, some statements need to be run many times repeatedly. DO – END statement:Syntax: DO I = A to B by C; < Loop Body >; END;Description:The index variable (I) starts with the start value (A), then is incremented by the increment value (C) each time (I=I+C). The iterations continue as long as the index variable is less than or equal to the stop value (B). If a negative increment is used, then the rules reverse so that the index variable decrements to a lower bound. Note that the start, stop, an