\(\TeX\) is a typesetting language developed by Donald Knuth. It takes source text together with a few typesetting instructions and produces, one hopes, a beautiful document. Beautiful documents use
” to delimit quotations, rather than the mundane
" which is what is provided by most keyboards. Keyboards typically do not have an oriented double-quote, but they do have a left-single-quote `
and a right-single-quote '. Check your keyboard now to locate the left-single-quote key ` (sometimes called the “backquote key”) and the right-single-quote key ' (sometimes called the “apostrophe” or just “quote”). Be careful not to confuse the left-single-quote ` with the “backslash” key
\. TEX lets the user type two left-single-quotes `` to create a left-double-quote
“ and two right-single-quotes '' to create a right-double-quote
”. Most typists, however, are accustomed to delimiting their quotations with the un-oriented double-quote
If the source contained
`"To be or not to be," quoth the bard, "that is the question."`
then the typeset document produced by \(\TeX\) would not contain the desired form:
`“To be or not to be,” quoth the bard, “that is the question.”`
In order to produce the desired form, the source file must contain the sequence:
``To be or not to be,'' quoth the bard, ``that is the question.''
You are to write a program which converts text containing double-quote
" characters into text that is identical except that double-quotes have been replaced by the two-character sequences required by \(\TeX\) for delimiting quotations with oriented double-quotes. The double-quote
" characters should be replaced appropriately by either `` if the
" opens a quotation and by '' if the
" closes a quotation. Notice that the question of nested quotations does not arise: The first
" must be replaced by ``, the next by '', the next by ``, the next by '', the next by ``, the next by '', and so on.
Input will consist of several lines of text containing an even number of double-quote
" characters. Input is ended with an
The text must be output exactly as it was input except that:
- the first
"in each pair is replaced by two ` characters: `` and
- the second
"in each pair is replaced by two ' characters: ''
"To be or not to be," quoth the Bard, "that is the question". The programming contestant replied: "I must disagree. To `C' or not to `C', that is The Question!"
``To be or not to be,'' quoth the Bard, ``that is the question''. The programming contestant replied: ``I must disagree. To `C' or not to `C', that is The Question!''