Question

A line of text is read from the input terminal into a stack. Write an algorithm to output the string in the reverse order, each character appearing twice (e.g., the string a b c d e should be changed to ee dd cc bb aa). 

Answer 1

1.   Ptr=top

2.   While (ptr <> NULL or ptr <> 0) do steps 3 through 5.

3.   { print ptr -> INFO, ptr -> INFO // print twice 

4.   Pop (stack, ITEM)

5.  Ptr=ptr-1

}