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can not perform recursion function correctly

hi: I want to use recursion function to transform a integer from binary form to ascii form. But the result is wrong.I don't why ,please help to analyse.

soure code:

void
binary_to_ascii(unsigned int value)
{

   unsigned int quotient;
   quotient = value/10;
   if(quotient !=0 )
       binary_to_ascii(quotient);
   putchar(value%10+'0');

}


int
main()
{
 while(1){
    binary_to_ascii(4267);
  }
}


I want to produce characters '4','2','6','7' in sequence. but the result is '4','4','4'. I don't know what is wrong with my code.

Parents Reply Children
  • No reason to not use recursion for cases where it gives an advantage. Finding examples of how a tool can be abused doesn't mean that a tool should never be used.

    no argument.

    The point is that if you do "C is C" and do not know the implications with the architecture, you have not taken the time to get to know the '51 aka "architectural ignorance".

    There are, indeed cases where a careful use of one of the features that have been wrested into C51 can be justified, but doing so just because "C is C" is plain foolish.

    Erik

  • I kind of expect an embedded developer to be competent enough to:
    1) Have a rough idea about mapping from C to assembler.
    2) Be able to look at disassembly if expectations doesn't match reality.

  • This case is not one of them - especially on an 8051!

  • Sorry - that post should have been titled, "use recursion for cases where it gives an advantage"

    In other words: I agree that recursion may, in general, be used where it gives an advantage (within the limitations of the implementation) - but the example at hand is not one of them!

  • Yes, this is a case of a linear problem that is trivial to rewrite as a loop. And as i noted earlier, the only state info the loop will need is one character/iteration since the loop produces the characters in the reverse order.

    Another alternative so instead produce the output in correct order is to have a sequence of operations handling 10^4, 10^3, 10^2, ...

    The recursive solution requires the return address for n iterations, and an unknown number of state bytes/iteration that will depend completely on compiler and optimization level. And how will the compiler know the maximum recursion depth?