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─────DO WHILE───────────────────────────────────────────────────────────────
 
     Action
 
     Executes a block of statements repeatedly while a logical condition
     remains true.
 
     Syntax
 
     DO [label [, ] ] WHILE (logicalexpr)
 
     Parameter          Description
 
     label              A label for an executable statement or a
                        CONTINUE statement
 
     logicalexpr        A test expression that evaluates to true or
                        false
 
     Remarks
 
     If <label> is used, the loop terminates with the labeled statement.
     If not used, the loop terminates with an END DO statement.
 
     A terminating statement must follow the DO WHILE statement and be
     in the same program unit. This statement must not be an
     unconditional or assigned GOTO, a block or arithmetic IF, CASE,
     CYCLE, DO, ELSE, ELSE IF, END, END IF, END SELECT CASE, EXIT,
     RETURN, SELECT CASE, or STOP statement.
 
     Execution of a CALL statement that is in the range of a DO WHILE
     loop does not terminate the DO WHILE loop unless an alternate-
     return specifier in a CALL statement returns control to a
     statement outside the DO WHILE loop.
 
     The following restrictions apply:
 
        ■ If a DO WHILE loop appears within another DO or DO WHILE
          loop, its range must be entirely within the range of the
          enclosing loop.
 
        ■ Two or more DO or DO WHILE loops may share one labeled
          terminal statement. An END DO statement may terminate only
          one DO or DO WHILE loop.
 
        ■ If a DO WHILE statement appears within an IF, ELSE IF, or
          ELSE block, the range of the DO WHILE loop must be entirely
          within the block.
 
        ■ If a block IF statement appears within a DO WHILE loop, its
          associated END IF statement must also be within that DO WHILE
          loop.
 
        ■ If a SELECT CASE statement appears within the range of a
          DO WHILE loop, its associated END SELECT CASE statement must
          also be within that DO WHILE loop.
 
        ■ Jumping into the range of a DO WHILE loop is not permitted.
 
      See Also: ◄$DO66►
 
      Example
 
           CHARACTER*1 input
 
           input = ' '
 
           DO WHILE ((input .NE. 'n') .AND. (input .NE. 'y'))
              WRITE (*, '(A)') 'Enter y or n: '
              READ  (*, '(A)') input
           END DO
                                    -♦-