POJ 1488 TEX Quotes

题目链接：POJ 1488

Describe:

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which converts text containing double-quote (") characters into text that is identical except that double-quotes have been replaced by the two-character sequences required by TEX for delimiting quotations with oriented double-quotes.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

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.

Output:

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!''

题目大意：

给好几行文本，EOF结束，要求将每一个引用的首个引号变为两个左引号``，另一对引号变为两个右引号''

解题思路：

思路就非常简单了，整个标志，来判断是第一个引号还是第二个引号，这道题之所以记录，是因这个字符串的输入问题，刚开始我用的是string类输入，发现不太好，空格不好解决，后来没办法在网上找的题解，发现dalao用的是getchar()，输入一个字符判断一下，学到了。

AC代码：

 

#include <iostream>
#include <cstdio>
using namespace std;
int f = 0; // 标志变量
int main()
{
    char c; // 接收字符
    while((c=getchar()) != EOF) // 这里可以用EOF来判断
    {
        if(c == '\n') cout << endl; // 换行则打印换行
        else {
            if(c == '"')  // 这里判断就简单了
            {
                if(f == 0)
                {
                    cout << "``";
                    f = 1;
                } else {
                    cout << "''";
                    f = 0;
                }
            } else cout << c; // 原样输出
        }
    }
}