TEX Quotes UVA-272

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which converts text containing double-quote (") characters into text that is identical except that double-quotes have been replaced by the two-character sequences required by TEX for delimiting quotations with oriented double-quotes.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

​ 　 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! ' '

HINT

简单的字符变量替换~

Accepted

#include<stdio.h>
int main()
{
    char ch;
    int flag=0;
    while(scanf("%c",&ch)!=EOF)
    {
        if(ch=='"')
        {
            if(flag%2==0)
            {
                printf("``");
                flag=1;
            }
            else{
                printf("''");
                flag=0;
            }
        }
        else printf("%c",ch);
    }
}