UVa272 Tex Quotes

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TeX Quotes

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 `` and " 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which converts text containing double-quote (") characters into text that is identical except that double-quotes have been replaced by the two-character sequences required by TeX for delimiting quotations with oriented double-quotes.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 and Output

Input will consist of several lines of text containing an even number of double-quote (") characters. Input is ended with an end-of-file character. 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: ‘‘.

Sample Input

"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!"

Sample Output

``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!‘‘

这道题的难点在于读入有空格的字符串和左右引号的判断。

解决方法是边读入边处理，使用getchar()读入单个字符，标志变量记录左右引号。

代码很短,如下：

#include <stdio.h>
int main()
{
  int c, q = 1;
  while((c = getchar()) != EOF)
  {
     if(c == ‘"‘){printf("%s", q ? "``" : "‘‘");q = !q;}
     else printf("%c", c);
  }
  return 0;
}

此处代码使用了2个小技巧：

                                  1.将赋值语句的返回值与EOF比较；

                                  2.？：运算符使程序简洁性和可读性大大提高。

UVa272 Tex Quotes

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原文地址：http://www.cnblogs.com/cuichen/p/4296176.html