DO and END Statements

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DO and END Statements

groups statements as a unit

DO ;

statements

END ;

The DO statement specifies that the statements following the DO statement are executed as a group until a matching END statement appears. DO statements often appear in IF-THEN/ELSE statements, where they designate groups of statements to be performed when the IF condition is true or false.

For example, consider the following statements:

   if x=y then
      do;
         i=i+l;
         print x;
      end;
   print y;

The statements between the DO and END statements (called the DO group) are performed only if X = Y; that is, only if all elements of X are equal to the corresponding elements of Y. If any element of X is not equal to the corresponding element of Y, the statements in the DO group are skipped and the next statement is executed, in this case

   print y;

DO groups can be nested. Any number of nested DO groups is allowed. Here is an example of nested DO groups:

   if y>z then
      do;
         if z=0 then
            do;
               z=b*c;
               x=2#y;
            end;
      end;

It is good practice to indent the statements in a DO group as shown above so that their positions indicate their levels of nesting.

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