----------
a3lo Loops
----------

  1 double CompoundInterest                     |
  2     (double Principal,                      |
  3      double Interest,                       |
  4      int Years)                             |
  5                                             |CompoundInterest
  6                                             |    (double Principal,
  7                                             |     double Interest,
  8                                             |     int Years)
  9 {                                           |
 10                                             |{
 11     double Value;                           |
 12                                             |  double Value;
 13                                             |  double D.1594;
 14     for (Value = Principal;                 |
 15          Years > 0;                         |<bb 2>:
 16          --Years) {                         |  Value = Principal;
 17         Value = Value * Interest;           |  goto <bb 4>;
 18     }                                       |
 19                                             |<bb 3>:
 20                                             |  Value = Value * Interest;
 21                                             |  Years = Years - 1;                           
 22                                             |                                               
 23                                             |<bb 4>:                                        
 24                                             |  if (Years > 0)                               
 25                                             |    goto <bb 3>;                               
 26                                             |  else                                         
 27                                             |    goto <bb 5>;                               
 28                                             |                                               
 29     return Value;                           |                                               
 30                                             |<bb 5>:                                        
 31                                             |  D.1594 = Value;                              
 32                                             |  return D.1594;                               
 33 }                                           |                                               
 34                                             |}                                              


1   A for-loop is translated in terms of 

    (a) An initialization part which is separated out.
    (b) A forward jump  to the loop condition situated at  the bottom of
        the loop.  If the  loop should continue  this condition  makes a
        backward jump to the loop body.
    (c) The increment  part of the for-loop  is added at the  end of the
        loop body just before the condition.

    Observe that  the above transformation actually  converts a for-loop
    into  a  do-while loop;  the  potentially-zero-iteration  path of  a
    for-loop is supported by a jump to the condition from outside of the
    loop.
   
2   There  is no  difference between  translation  of a  for-loop and  a
    while-loop.